I have a particular soft spot for the Wonderwall/Boulevard remix.

the Kanye West and Daft Punk mix up combined with the Akira Montage music video wasn't too bad.

Final Fantasy and Sonic the Hedgehog remixes are plentiful good.

A con I recently went to played some songs like Offspring - Pretty Fly for a White Guy, Backstreet Boys - Are back, Green Day - Basket Case. but they were all sung by a little japanese girl. Pretty weird.