Get a small glass of beer or whisky or any drink (water/juice). Then put it under a hat so it cant be seen. Then tell people that you will be able to drink the liquid from the cup using just a straw without touching the hat with anything.
Then put the straw next to the hat or a little underneath it (dont grab the hat with ur hands) and breathe in. Then after a while say that you have finished the glass. Of course they wont believe you... so when they say no you havnt just tell them that you have and if they dont believe you then take a look.
They will then lift the hat up and thats when you pick up the glass and use the straw to drink it all! You just drank the liquid using just the straw without touching the hat with anything! Congratulations, thats about $5 in your pocket (or a round of drinks, depending on what your bet was!)
Nerdywow!