Time-locked Lottery Contract
So, we start the contract off with a bunch of Ethereum. The eth will be available for withdrawl after a certain amount of time but to release it, you must send in a small eth fee. The eth fee will build the next pot. Hopefully enough people send a request at the same time, essentially racing for the reward, that there is enough eth to make the next pot decent.
This is such a dumb idea. Easily broken by miners because of timestamp manipulation.