Aha. I'm glad you asked. Since this will be the main thread for the main ponzi game site, I'm happy to explain.
The reason there's not much info on the site is that it's assumed players already know how this works. I see you are new to the forums, so please allow me to explain.
These are ponzi games. A ponzi is when later bettors pay off earlier bettors. Ponzi schemes http://en.wikipedia.org/wiki/Ponzi_scheme
are names after Charles Ponzi. He ran several ponzi "schemes" in the 1920's, and the way he did it was shady and illegal.
The difference here is that the game is completely transparent. There are no secrets. It's an acknowledged gamble.
Theres the pot, this is how much is available to pay the bettors
There's the jackpot, that's what the last bettor in will win when the round expires.
Rounds expires after X hours with no one placing a bet.
So, let's say we have a round with a 10% ROI and a 10% jackpot.
The round creator puts in 1 BTC. 0.1 of this goes to the house, this house fee is only on the very first bet of the round.
* So, 1 BTC in. With 10% ROI, he expects to get paid 1.1 BTC. 0.1 goes to the house, 0.1 to the jackpot. The pot is now 0.8 BTC
* Bettor #2 puts in 1 BTC. 0.1 goes to the jackpot, which is now 0.2, and 0.9 to the pot, which is now 1.7
The 1.7 pot is enough to pay bet #1, so he gets paid 1.1. The pot is now 0.6
* Bettor #3 puts in 0.5 BTC. 0.05 goes to the jackpot, which is now 0.25, and 0.4 goes to the pot. The pot is now 1.1
The 1.1 pot is enough to pay bettor #2, so he gest paid 1.1 The pot is now 0.
* Bettor #4 puts in 1 BTC. 0.1 goes to the jackpot, 0.9 goes to the pot. The pot is now 0.9
0.9 is enough to pay bettor #3 his 0.55. The pot is now 0.35
until no one puts in a bet for x hours (24 or whatever is the number for that round) and the last person in wins the whole jackpot.
All the variables, the pot, the jackpot, the min and max bet, the number of hours before the round expires, they are all visible at all times. You can make an informed decision before you place a bet.
Some bettors will lose their BTC. That's why it's called gambling.
Look at some of the existing rounds. See for yourself how a high ROI affects the game vs a low ROI, and similarly how a high vs low jackpot affect the games. Make an informed decision, and place a bet if you feel confident.