Our friend Matt and my brother Nick were playing Halo and we get in an elevator for a scene and so he said "hey Nick, you wanna know what's fun to do in an elevator?" then Nick said "what?" as Matt threw all his grenades... It has become a really funny inside joke to say "you know what's fun to do in an elevator?"
All good answers some more funny than others. The one u don't want to do is hit the red stop button. On the new elevators the red button locks out the others. So probably u will be embarrassed when confronted by security or FD. There are two more good ones: start singing God Bless America; bring a whoopsie cushion and see what happens. Enjoy.