Okay, now this is not up there with the cult following of the Hitler's Downfall videos, but there are quite a few of these take-offs on Beyonce's "All the single ladies." Here are some of the more enjoyable ones that I found.
Beyonce's Original Video
This baby has some moves!
Joe Jonas?! Really?
I don't know if you've seen the new series "Glee" but it's awesome! This was from one of the episodes. Wait for it, it's good.
I'm still trying to find one of the earliest take off videos of the teenage guy who does this in his bedroom. His choreography was amazing. I think he even went on Oprah or Ellen or something because it was so good. Anway, after that everyone started making their own videos. I'll keep looking.