Everyone post a random 5 digit number and send you 100 sats. They can guess as many times as they want. Put all the sats in a pool, after 30 mins, use a RNG to get a random 5 digit number. The one that posted the correct number wins the pot. If nobody wins, the pot rolls over the next drawing. It can get to be a very big pot after a few drawings. Exciting 😆