I do so agree with you SOP. The encapsulation of a story, a message, an idea and a sales pitch into 30 seconds is hard enough - to make it amusing and entertaining is an art form in itself.

Here's some of my favourites:

http://www.youtube.com/watch?v=KkBIIZcLmQQ&feature=PlayList&p=B2A52C2AEB4268EC&playnext=1&playnext_from=PL&index=5