Fietscafe: Pub on Bike.

From the website:

The Fietscafe is a mobile pub, for groups up to 17 people per bike, who can transport themselves by moving the pedals.

Not all guests do have to cycle; the Fietscafe® is provided with 10 freewheels, so you can change seats from time to time.

You need a sober driver and of course, the best bartender looks after the beer and drinks.

http://www.fietscafe.nl/engels/index.html - Thanks Alec!