The DumpsterWhen we were grade-school aged, we lived next door to our grandpa Sever's grocery store / meat market. They had a dumpster where all of the store trash was kept on the side of our house. It sounds disgusting now (think of all of the meat scraps that must have been in there), but we used to love to get inside of that thing to play. We'd hunker down, with the lid closed (it smelled aweful!) and pop up and yell at passersby. That was great! I've always loved popping out of nowhere at people and surprising them. I still do it in the store very occasionally, when I'm feeling particularly silly.
When we were a bit older, we moved not too far from a WalMart. I used to go to the clock section, and just for fun, I'd set all of the alarm clocks to go off at the same time.
In Front of a Fancy Restraunt
When I was in college, a large group of us went to a fancy restraunt together. We had to wait for about an hour to be seated. They had us waiting outside, next to a large window where we could see people eating. I faced the window and started doing my crazy arm swinging thing. Another guy in our group had a similiar arm flailing thing that he did that was really funny too, so he started in. I actually saw a woman, in the restraunt spit out her food because she was laughing at us.