Andy Rehfeldt makes really cool mashups using the the video feed and singer's voice from a famous song dubbed in with his own version of the same song performed in a totally different style of music than the original. It might not sound like such a great idea, but it turns out the mashups are highly listenable and funny as hell to watch. There are lots to pick from when you look through Rehfeldt's YouTube channel.
But to get an idea, check this one out. AC/DC Back in Black, funk version..