While you're (most likely) wasting time on the computer, it doesn't hurt to take a bit of time to help. This first link leads to the thread where you can donate by clicking a link. In that thread, you can find a code in the first post to add those links to you Myspace, Facebook, Xanga and (as I recently discovered) your UG profile.
The second link is for a donation to find a cure for cancer. It's the same as the other links, no monetary donation required, all you have to do is click a link.
The third link is Google but with a black background instead of white. The theory is that it takes less energy to light up a black pixel than a white one thus it saves energy. But judging by the "About Blackle" link, there's no solid evidence. However, it's good to set it to your homepage just in case.