I don't usually futz around with Facebook games too much — Neopets and Scrabble knock-offs notwithstanding — but Hive7's Zen Garden donates 10% of profits to breast cancer cure research.
Zen Garden is one of those social games that's all about trading things for more things and buying virtual currency in order to buy more things to trade. The things you're buying range from flora and fauna for your garden to fancy objects and terrain tools you can stick in your virtual garden to create a 2D space of zen. The rate of exchange is currently 99 cents to 1000 Zennies and a lot of the good stuff — like a cascading fountain — goes for under 500 Zennies.
Starting last month and continuing through May 21, 2010 next year, Zen Garden will donate 10% of all Zennie purchases with a minimum donation of $US25,000 to the Susan G. Komen for the Cure foundation. By the end of 2009, Hive7 hopes to collect $US10,000 in donation funds — at the moment, they've already got $US5,000.