From a group page on Facebook, here are my top 10 things to do in a lift (elevator, for our friends across the pond) when you're bored:

1. Shave.
2. Offer nametags to everyone getting on.  Wear yours upside-down.
3. Stand silent and motionless in a corner, facing the wall, without getting off.
4. On the top floor, hold the door open and demand that it stay open until you hear the coin you dropped down the shaft go "plink" at the bottom.
5. Stare, smiling, at another passenger for a while, then announce "I've got new socks on".
6. Bet the other passengers you can fit a coin up your nose.
7. Leave a box between the doors.
8. Say "ding!" at every floor.
9. Announce in a spooky voice, "I must find a more suitable host body...".
10. Put a desk inside and ask anyone who gets on if they have an appointment.