Saw this video tonight, and I absolutely love it (oh, one word of warning - the language is a bit fruity).
It's purpose is to encourage voter registration, and it is fronted by pretty much any famous person you can ever think of (the full list is on the side of the video on the YouTube page for anyone trying to play guess the celeb). But two particular features stand out as being important.
First, this is designed to be a piece of viral marketing. The participants actually encourage viewers to forward it onto five of their friends. The results are impressive. The video launched on the 1st October. Coupled with another version of the video with the swear words bleeped out, it has been seen more than half a million times.
Second, and as important, is the way the video is tied in with additional web-based data, especially this information, stored on Google maps. It you go to that site and enter your address, you can find out about voter registration rules in your state, check the register to see if you are already on the electoral roll, and access all kinds of useful information.
Very impressive and imaginative.