Rules: the current winner posts a topic. Everyone else tries to find and post a link to a music video that meets the topic. After a while, the last winner declares entries closed, then anyone can vote on the submitted songs (but you can't vote for your submission). After awhile, the last winner closes the voting, totals up the vote, possibly roles a die for ties, and declares a new winner, who then repeats the process by choosing a new topic. Also, try hard not to repeat previous topics. You can vote, even if you did not submit an entry for a particular topic.
Edit: Before you vote, you are honor bound to listen to the first minute of each entry.
Some previous topics that I know we used:
Songs or groups referenced on these forums. Feel free to add a post someowhere that then qualifies. I know I've referenced a group, and at least 4 songs, already, so get hunting.
http://www.youtube.com/watch?v=LfmrHTdXgK4 Queen's Flash