o wow, that's so funny.
i know a whole bunch of things to do in the elevator or bathroom. here are some bathroom ones that i remember:
1. make constipated noises, then drop a watermelon from about 6 feet up into the toilet bowl, and sigh.
2. put peanut butter on a piece of toilet paper, and drop in under the wall between your stall and the 1 next to you, then ask the person next to you if he could kick it back over.
3. bring an extra pair of shoes, and something long and sturdy(like 2 thick sticks). put the sticks in the shoes, put your pants on them, so from under the wall it looks like the bottom half of a person, and you're standing in your shoes and no pants on, then grab the "person" and make sex noises.