fun thing to do in an elevator number 43: Paint it to look like the tardis on the inside, Put on a bow tie and jacket. When the door opens tell people to get "all onsies".
put a box in the corner then ask if anyone hears ticking, or, when there are four people in the elevator with you, stand at the door (when it is closed) and say something to the effect of "you must be wondering why ive gathered you all here otday..."