Elevator John

Take a normal high-rise building and transform one of the elevators into what looks like a bathroom stall. Then, place cameras on the elevator and on various floors and catch peoples reactions when the door opens and sitting right there a foot away is one of the guys reading the newspaper and taking a shit. You could also split the elevator and have 2 stalls with 2 dudes taking a plop. Make the thing stink to high-hell, add flush sound effects, maybe a toilet overflowing and one of the guys plunging with his pants down.