Kalculate Charity Drive
When: Saturday October 27, 2012 midnight to midnight PDT
Rules: The creators of Kalculate will donate a dollar to charity for every registered user that plays a full online game--up to a maximum of $1400! All you have to do is play.
About the Game
Kalculate is a you vs. the Internet style game for math lovers. The rules are simple: answer as many math problems as you can in 90 seconds. At the end of each round, Kalculate will tally up all the scores and show you where you ranked relative to others currently playing.
Tip: answering 3 questions in 10 seconds earns you a score multiplier
If you prefer to just practice and stay out of the competition, there's an offline mode that allows you to play solo.
Kalculate is free (ad-supported) and can be downloaded here.