Lottery tickets!!

What matters is the "expected return". If you don't understand that, you shouldn't be gambling. In most states, the expected return is ~$0.50 for $1.00 gambled. The mafia numbers games gave returns of ~$0.90, which is why they are still in business. When the pot rolls over, you have an opportunity to get >$1 return since you get a chance at money already invested. However, as more people pile in, the rolled over pot gets diluted, so my guess it will be <$1 return. Anyway, I put in $5 to a pool at work because I thought it might be >$1 return and not worth my time to investigate.

Oh, and never bet on your birthday or such. Birthday numbers fall in certain clumps, so aren't spread evenly over all numbers, which reduces your expected return. Better to bet on the sparser numbers, if you can figure out what those are. Of course, if you believe in "lucky numbers" you shouldn't be gambling. Better you chase Leprechauns for their gold pot.