A few to view (most of which you've probably heard):

http://www.youtube.com/watch?v=ueOgZPBXY4A
(and if you like that, watch this video with a very funny misheard lyrics interpretation: http://www.youtube.com/watch?v=LucfKdukf10)

http://www.youtube.com/watch?v=O3sGTaQ9s9c

http://www.youtube.com/watch?v=G0T-gxtVUzM

http://www.youtube.com/watch?v=xWHf_vYZzQ8

http://www.youtube.com/watch?v=Y-VifE8EK8w