Bet that you can make a raw egg stand on end. Let your sucker try first. They'll never be able to do it unless they know this little secret; Shake the egg violently. Doing so breaks the yolk and makes it sink to the bottom of the egg thus lowering it's center of gravity. Otherwise the eggs center of gravity is pretty much in the middle of the egg and it tips sideways. If you shake the egg enough and then give the contents time to settle, you'll be able to make the egg stand on end.

Another way to do it is to place a little salt under the table clothe when no one is looking. Place the egg on top of the hidden salt and the salt will support the egg.

Yet another way is to put some salt on your palm and then lick the egg and rub it on your palm. The salt that sticks to the egg will support it.