We had an amazing time yesterday with a group of 15 of our friends doing the beer bike Aachen, which is essentially a self propelled pedal powered bar we drive around the streets of Aachen (The actual driver was from the company). We had some great mix CDs and all had a blast! I snapped this when we stopped in front of the town hall. I am natually missing from the group, as well two guys ran off before I could corral them for the shot. If you want to know more about the beer bike check out http://www.bierbike-aachen.de/
also I think it also exists outside of Germany, see if you can find it in your area, it was a blast!