A great party icebreaker.
You need a friend who has no hang-ups about his/her nose to do this. Sit on a chair and ask your friend to blindfold you. Your friend should then sit on a chair directly in front of you with his back to you. Now reach round and place your right hand on your friend's nose.
Now put your left hand on your own nose, and then gently tap and stroke both noses at the same time with identical movements. After about a minute, this gives around half of participants the feeling that their nose is 3ft long, or that it is somehow elsewhere.