A great new and very easy way to give back: Google Chrome for a Cause. Each and every tab you open between dec 15 - dec 19 raises money for a charity. It's really that simple.
Update: I wrote this post shortly after I set-up the Google Chrome for a Cause. Since then, I've already had 2oo tabs! It really does add up quickly and can go towards planting trees, providing vaccines, books, clean water and shelter!