When I was a kid...and sadly, on more than one occassion...I spit in the air while on the swings...at the back apex...I have a pathetic collection of complete brainless activities which occurred in my youth for which I can offer no explanation. This one is actually mild.
Let one slip in the elevators when my office is on the 10th floor.... then get off the elevators only to watch your fellow co-workers board the same elevator to go down to the lobby!