Ask around the table who has fast reflexes. Get a $10 bill, scrunch it a bit and put it on the table (a bit like a ball). Ask the person to position their hand some 4 inches above the bill, palm down. Then, position your hand much higher (1.5ft) also face down and bet that person that you can grab that bill before they do.

It's misleading because of the distance but if you're just normal fast by the time they react you'll already have the bill in your hands.

If you smoke, the smoke waterfall is neat and easy.

Take your pack of cigarettes and pull the cellophane down to create some space between the cellophane and the box. Using your lit cigarette, carefully melt two holes on the lengthwise ends of the cellophane, and then push the cigarette lit end first into one of them. If done right, the smoke coming off the cigarette will make a little waterfall and pool of smoke.