Here's one for a pool table. Put a ball directly in front of each of the six pockets, and put the cue ball anywhere in the middle of the table. Bet your mark that they can't get every ball on the table into a pocket without scratching with only a dozen shots.

The trick: After they make each of the six balls into their respective pockets and declare victory, bring up the cue ball. It's a ball that was on the table at the beginning of the bet. If it's still on the table, they lose. If it went into a pocket, it's a scratch, and they lose.