Thanks for all the comments and questions.
The system is simple: There is a internal counter, that will select the winner of every 3rd transaction that get 3+ confirmations. You can transparently check all the transactions when they got approved and etc, with the block explorer.
So, you can try to get your transaction confirmed -using the fees- to put your transaction on the winner spot.
The math behind is this
bet 1: 0.001 BTC
bet 2: 0.001 BTC
bet 3: 0.001 BTC
bet 3 wins: gets bet 3 + bet 2 (0.001 + 0.001 = 0.002 BTC)
The house get bet 1 (0.001) minus the transaction fees to send the winning transaction back.
When the volume of transactions is high enough we can increase the winning multiplicand to probably 2.6. But we are not there yet.
I'm more than happy to answer any other question you have.