The students on my leadership team hosted skateboard Olympics during lunch hour last year in the cafeteria. They were a hit! We first had a couple students who were good at tricks demonstrate their stuff. Then we had the silly Olympics for the rest of us.
There was rowing (sitting on the skateboard using a short toilet plunger to paddle), Skiing (standing on the skateboard using two toilet plungers on broom handles to push yourself), and swimming (laying on your stomach on the skateboard using your hands to push yourself). Lots o fun and low cost. Could be spruced up by having color teams, other special accessories to make contestants look ridiculous such as touques, gloves and ski goggles, swimming caps and snorkeling masks, lifejackets.