Funbrain Created for kids ages preschool through grade 8, Funbrain offers more than 100 fun, interactive games that develop skills in math, reading, and literacy.
Math Monday Math Monday is a weekly drop-in lunchtime activity where students of all ages can get hands on with math games, puzzles and manipulatives that help build their math skills.
Nrich.maths Math puzzles and activities for all ages, with a theme that changes each month. Plenty of interesting puzzles in the archives, too. Hints available, and solutions for past problems.
Primary Games A lot of fun math games to reinforce counting, telling time, fractions, arithmetic, strategy and more.
Sheppard Software Free online games with the goals of adding sound and visual effects to make learning fun and more memorable, designing games with many difficulty levels so that players will continue to be challenged no matter how far they progress, and providing games that will exercise players' brains.