Okay, in future, no one let me near Youtube and the phrase "mashups" when pished.
Scifi:
http://www.youtube.com/watch?v=C54yPPiQMfw - nearly busted something laughing too hard.
http://www.youtube.com/watch?v=WyfhzqhJNbg&feature=related - cackled till I died
Music:
http://www.youtube.com/watch?v=3CTJqwX-AwM - BEST FUCKING MASHUP EVER.