I'm a big astronomy buff. So I was totally suckered when my sister sent me a link to the Stardust@Home project.
No more silly blogs, or time-wasting movie trailer. No, I'm afraid I'm too busy making a contribution dude! With the Stardust@Home project people like you and me can actually help out with the grunt work of a real astronomical project. It's a collaboration "consisting of thousands of volunteers all over the world, and professional scientists at U. C. Berkeley and NASA/JSC."
Basically, after a brief tutorial, you examine a series of slides of Aerogel under a "virtual microscope" looking for dust that was picked up by collectors on the tiny spaceship Stardust. (I'm not kidding) On its seven year journey through the solar system it flew around, flew behind Comet Wild 2's coma, picked up some interstellar dust... This is seriously cool, if slightly geeky, stuff.
So if you're looking for a new and useful way to waste your time, get your lab coat on and check it out.