Google has recently started bringing in people to speak on various tech subjects. They are recording the talks and putting them up on Google Video. These talks are known as "Google Tech Talks".
If you're a geek at all, many of these tech talks are quite interesting. But I found one in particular that I absolutely adore. It's a presentation given by Luis Von Ahn about "Human Computation", or utilizing people on a massive scale to solve conceptually simple problems that computers can't.
You can watch the video here. It's both informative and quite entertaining.
The basic idea is to turn these problems into fun online games. The two games that are out so far are The ESP Game and Peekaboom. Both are quite fun, but the best part is that by playing them you are doing something genuinely useful!
They have a new game out now, called Phetch. Apparently it's still in beta, but it's very fun as it is.