Nim

Effect: Play a game with your friend that you can always win

Secret: This is a game called "Nim," and it's a con-man favorite. There's a million variations (we'll learn more later), but here's a super-simple starting one:

Lay down 17 pennies, matches or any other tokens. Explain to your friend that you'd like to play a game where each of you take turns removing 1, 2, or 3 pennies from the pile. The object is to NOT take the last penny.

To win, all you need to do is make sure your friend goes first and watch how many pennies he takes. If he takes 1, you take 3. If he takes 2, you take 2. If he takes 3, you take 1. In other words, for you to win, the total pennies taken each round should be 4.

As long as you follow this rule, you can't lose!

Note: If you want to get maximum enjoyment out of this trick, make sure that when you teach the rules to your friend, you lose the first few games, just to get his confidence up. Later, once he feels comfortable with the game, you can start betting lunches, drinks, or anything else!

BONUS: Sooner or later, your mark will get suspicious, and ask YOU to go first... no problem! Just keep one extra token palmed in your hand the whole time you play. Whenever you go first, reach in and grab a token while you release the one in your palm. Now you've gone first, yet the total count is still 17 tokens (and now it's their turn).