Bar bets

[TPL]

Just trying to prepare for the holiday party season. I'm looking for some good bar bet ideas. I know of a couple:

1. The same birthday bet: Bet someone that you can poll 30 people in the room and find 2 that were born on the same date (not including year). I believe the math works out that this works over 99% of the time. With these odds, I feel I can bet whatever amount I can pay off in the even that 0.5% outlier occurs.

2. 1,089: Have someone write down a 3-digit number, with no digits the same. Tell them to reverse the numbers, and if it's less than the original number, write it directly below. If it's more than the original number, write it directly above. Now, subtract. Ask them if the number is less than or more than 100. If it's less than, tell them to write a 0 in front. Now, they need to reverse those numbers and write it below this third number. Add. It will add up to 1,089.
Ex:
583
-385
=198
+891

=1,089

More of a math trick, really, but I figure if you wait to place the bet until after the math is done, there's bound to be a sucker that will see 1,089 and think I messed up and take the bet.

Any others?

TPL