Funbrain
Math & Number Games
Order of operations, multiplication, place value, etc.

NCTM Electronic Examples
Examples to help teachers understand and teach math concepts; can be shown to the whole class with a projector

Project Interactivate
Many, many interactive applets to help you teach math concepts.  My favorite is the Tesselation tool!  So cool!

A Maths Dictionary for Kids
Interactive dictionary that gives brief, easy to understand definitions for math terms.  Well worth a look-see.

Cyber Chase Games
30 math games, based on the PBS series, CyberChase

A+ Math Flashcards
Interactive flashcards for practicing all basic math skills

A+ Math Games
Math-O, hidden picture, and concentration to practice basic skills

Primary Games
Scroll down the page to find games on fractions, angle estimation, basic facts, even & odd numbers, negative & positive coordinate grid, 1-100 number squares, and more

Primary Games - More
Fractions, addition, place value, coordinate graph, mental arithmetic, sequences, and more. (demo versions, the word "demo" appears in the background of all games)  Also has supporting worksheets for some games.

Interactive Math Examples
Tally chart, pie chart, pictogram, probability spinner, bar graph, line graph, geoboard (quadrilaterals, triangles), counters, class count, function machine, cuisenaire rods, fraction maker, ordering numbers)

Interactive Math Examples
Equivalent fractions, number line, polygons, clock, estimation, angles, coordinates, fractions bars, hundred chart, place value cards,  percentage

Kids' Domain

Math Games
Ages 6 and up

Child U
This is a paid service website, however, there are some sample
activities you can play for free.
Scroll down the page to access activities in the following areas & grade levels:

3rd & 4th Grades
Math
Right, obtuse & acute angles, slides, flips & turns, polygons, leaf & stem graphs

5th & 6th Grades
Math
Geometry

BrainPop

Short math movies.  Printables and activities to go with.

Zeeks

Math Games

KidsHub

Math Games
Arithmetic, geometry, math puzzles, and algebra games

Multiplication Game

Base 10 Blocks

National Library of Virtual Manipulatives for Interactive Mathematics

Choose from a variety of virtual manipulatives, sorted into grade levels, PreK-2, 3-5, 6-8, 9-12

Teaching Tables
Several multiplication games
(demo versions)

Teaching Time
Games that teach time telling skills

Practice math skills
Basic facts, money, graphing, measurement, comparing numbers, and place value.

FunSchool
Use the game guide to search for math games for all grade levels

I Know That
Math games (requires sign up to access free games, remainder of games requires a subscription)

Learning Planet
To access all games requires a subscription($39.95/year); free trial available(click here for more information); free math games listed below:

Number Train
Count Your Chickens
Time Works
Spacey Math
Math Mayhem

Prongo

Ages 6-12

Batter's Up Baseball

2-Player Math Game (Addition)

Lemonade Larry

Farm Stand

The Guessing Game-Guess the Number

GameQuarium

Lots of learning games from all over the Internet, organized here by grade level, then by subjects.

123 Games

Money Games

Time Games

Math Games
Place value
Addition
Subtraction
Multiplication
Division
Mixed practice
Problem solving
Fractions
Decimals
Geometry
Pre-algebra
Measurement
Data interpretation
Online math tools
Teacher sites

Scott Foresman E-Tools

Wow!  These are some very useful tools.  They include:

Place Value Blocks
Counters
Money
Time
Fractions
Probability
Spreadsheet Data Grapher
Geometry Shapes
Geometry Drawing

Interactive Math Games
Fun and kid-friendly math games.  For example, in one of the games, you must create the given angle to find bananas for the monkey!

FunSchool
Use the game guide to search for reading, words, and vocabulary games for all grade levels

I Know That
Language games (requires you to sign up to access some free games; the rest of games require a subscription)

Learning Planet
To access all games requires a subscription ($39.95/year); free trial available (click here for more information); free reading game listed below:

ABC Order
(Pre-K-3)

Kids' Domain

Reading Games
Ages 3-6

Reading Games
Ages 6 and up

GameQuarium

Lots of learning games from all over the Internet, organized by grade level then by subjects.

ABC Games

Language Arts
Vocabulary
Sentence Structure
Spelling
Punctuation
Word Fun
Parts of Speech
Harry Potter
Dr. Seuss
Student created games

Spanish

Games divided into categories such as:
Math & Science
Art & Music
Brainteasers
and more...

KidsHub
Language games -- spelling, writing, word games, and more

Contains the following sections:

Phonemic Awareness

Phonics

Word Study Skills

Vocabulary 

Reading Comprehension

Integrated Units

Prongo

Drag & Drop Game
(Age 3-6)

Child U
This is a paid service website, however, there are some sample
activities you can play for free.
Scroll down the page to access activities in the following areas & grade levels:

1st & 2nd Grades
Language
Phonetic skills, rhyme & literature,  oceans

3rd & 4th  Grades
Language
Interjections, conjunctions, prepositions, reading strategies & techniques

5th & 6th Grades
Language
Story elements, writing paragraphs & essays

Brainpop

Short English movies and printables

Magnetic Poetry

Click and drag words around the screen to create a poem.
You can then type your poem at the bottom of the page and 
print it out!

Kids' Domain

Animal Games
Ages 6 and up

GameQuarium

Lots of learning games from all over the Internet, organized by grade level then by subjects.

Science
Space
Ecology
Human Body
Energy
Dinosaurs
Animals
Oceanography
Matter
Natural disasters
Cells

BrainPop

Short movies to watch and activities to do and print
Requires paid registration 
Does have some sample movies for free

Science - click on link at top

Solar System Trading Cards
Answer questions abou the solar system correctly to collect "trading cards"

Child U
This is a paid service website, however, there are some sample
activities you can play for free.
Scroll down the page to access activities in the following areas & grade levels:

4th & 5th Grades
Science
Igneous, metamorphic & sedimentary rocks, kaleidoscopes, flashlights, & mirrors

Beakman & Jax

This page is also protected, so once you get inside, click "Interactive Demos" to get to the activities.
Activities here include:

What does smoking do to your lungs?

How does a remote control work?

What is earwax?

What is a magnet?

What's in blood?

What is relativity?

How does the Internet work?

Why do leaves change colors in the fall?

How do cellular phones work?

How does gravity work?

How does the moon power the tides?

How does a sundial work?

What does "squaring" or "squared" mean?

Why does the moon look bigger on the horizon?

Learning Planet
To access all games requires a subscription; free trial available; free game listed below:

Geography Quiz

GameQuarium

Lots of learning games from all over the Internet, organized by grade level then by subjects.

Social Studies
U.S. Geography
World Geography
American History
Economics
Black history
Africa
Presidents
Canada
Australia
Egypt

Child U
This is a paid service website, however, there are some sample
activities you can play for free.
Scroll down the page to access activities in the following areas & grade levels:

4th & 5th Grades
Social Studies
Maps, Uncle Tom's Cabin & slavery issues

Extras
Just for fun games, matching, share your opinion, connect the dots, etc

GameQuarium

Lots of learning games from all over the Internet, organized by grade level then by subjects.

Color  Games

Shapes Games

Brainpop

Short movies & activities on various miscellaneous subjects - requires paid registration - does have a few freebies, however.

Destination Modern Art

Take a tour inside the Museum of Modern Art with a friendly alien.  Each piece of artwork has accompanying interactive activities.

Learning Planet
To access all games requires a subscription; free trial available; free games listed below:

Pre-K-3

Mr. E's Memory Game

GameQuarium

Lots of learning games from all over the Internet, organized by grade level then by subjects.

Brain Teasers

Music

Safety

Keyboarding

Holidays

FunSchool

Lots of fun learning games, divided into grade levels and subjects

Search for Games
by grade level and by subject

Games for Preschool

Games for Kindergarten

Games for 1st Grade

Games for 2nd Grade

Games for 3rd & 4th Grades

Games for 5th & 6th Grades

Printables & Downloads

Learning Planet

Preschool - Kindergarten
Number Train
123 Order
Count Your Chickens
Alphabet Action
ABC Order
Mr. E's Memory Game
Rats!

1st - 3rd Grade
Spacey Math
Crossword Puzzles
Word search puzzles
Mr. E's Memory Game
Rats!

4th - 6th Grade
Crossword puzzles
Fraction Frenzy
Geography Quiz
Lunar Adventure
Math Mayhem
Mr. E's Memory Game
Rats!
Spacey Math
Word Search Puzzles

Prongo

Ages 3-6
Fish World Game
Memory Match
DinoDraw Game
18 Mazes!
Hatch & Match
Drag & Drop Game

Ages 6-9
Batter's Up Baseball (math)
CopyCat Jack Game
Hungry Caterpillar
Stock Market Game
DinoDraw Game
2 Player Math Game
Lemonade Larry (math)
Farm Stand
18 Mazes!
Connect the Dots
Word Find
Puzzle Game
Space Jumble Game
The Guessing Game
Tic Tac Toe

Ages 9-12
Batter's Up Baseball (math)
2 Player Math Game
CopyCat Jack Game
Hungry Caterpillar
Checkers
Lemonade Larry (math)
Stock Market Game
Space Jumble Game
Word Find
Farm Stand
18 Mazes
Puzzle Game
Connect the Dots
The Guessing Game
Tic Tac Toe

Power to Learn

Various learning games, including games on the solar system, math, and freedom

Quizlab
$

This is a paid subscription service that allows you to create your own online quizzes that are automatically graded for you and stored in your account.  The price for a one year subscription is $29.95.  Well worth every penny.

Quia
$



$ -- This is now a paid service -- Subscription cost is $49/year
Click HERE to see more information.

Awesome resource!  Create an account, then make your own matching
games, concentration game, flashcards, hangman game, jumbled
words game, multiple choice quizzes, challenge board (like the
game show Jeopardy), ordered list game, jumbled words game, and
Rags to Riches game (like Who Wants to be a Millionaire game show).  
Students love to review using these games.  If you have a PC to TV converter,
you could play your games with the whole class at once!  

Choose from thousands of games created by other teachers.  Create your own games, using the information you are learning in class.  Quia also offers a class web page that you can set up in just moments.

Bonus.com

This site has lots of games, however, it is in a protected window.
Click the green rectangle labeled "Brains" at the top of the main page once you
get inside to access the activities.  Titles are as follows:

Dinosaurs
Blast Off
The Earth
US History
Beakman & Jax
Homework Help
Natural Disasters
Field Trip
Cities & States
What's Inside? (human body)
America
Under the Sea
Going Places

Board games
Arcade games
Card games
Brain teasers
Puzzles/Mazes
Gadgets
Art/Music
Sports
Mindless Fun

Carmen Sandiego

Students must sign in with their own name and password, then
they get to help find Carmen Sandiego through a series of
fun, educational games!  It's all free, and it's all fun!
Do NOT miss this great site!

Coach

Make your own puzzles (crossword, anagrams, word search, and more).
You can play them online or print them out.