I used to find long flat stretches, usually a lunch table at school, and would try to glide pieces of paper along the length by blowing behind the paper.
The idea is to get an air cushion to build beneath the sheet, lifting it and propelling the paper down the platform. I would often try to beat distance records, or several of us would get together to race to the finish line.
This eventually led to the construction of intricate designs of racers/airships.
Tons of fun, and it even works on a classroom desk, if you're off in a corner and nobody is paying too much attention to you! Gotta love ADD!