Looks like after seeing the electronic billboards, the trucks with advertising on them, and occasionally small car/bike advertising, we now have a new player in the on the road / off the road adverting area.
Vitamin Water had this guy pushing his specially modified bike through Shibuya promoting their product. From the number of stares he was getting it appears the form of advertising was working at least for its novelty factor.
Here is the product being advertised. You have probably seen this in your local supermarket or convenience store.
What other strange forms of advertising have you seen in Japan on the roads / footpaths ?