Do I Smell A Pencil?

This Transport for London spot has been apparently passed around since about March 10 and has been posted on several other blogs already.  This is for a few reasons.
1) The spot is just brilliant.  A practical case study in viral by Seth Godin's definition. 
2) The site, in a way that I don't think I've ever seen done before, practically tells its audience to share its content with others.
I love it.  It's original, simple, inexpensive, and without a doubt, effective.  I'll be disappointed if it doesn't win big at award shows.