Ok, I was getting a bit despondent with all the over-the top Ponzi schemes floating around, especially with all the creators taking 10% for doing nothing. So I put together my own (from scratch, no copy & paste) with 0% going to the creator and a 125% return, i.e. while deposits to it are ongoing you get back 125% (1.25x) of what you put in.

Basically send between 100 finney (0.1 ether) and 10 ether to (like the 1.25 multiplier, the 10 ether maximum is set "low" to allow payout flows)

0x43bbc7fafb860d974037b8f7dd06b6f6fe799b3e

Source code is also attached on etherscan.io for verification purposes. It is simple, no frills, no fuss.

http://etherscan.io/address/0x43bbc7fafb860d974037b8f7dd06b6f6fe799b3e

As with all these things, there are risks - if the deposits stops, you are out of luck. While people are playing, you will get your returns. I would recommend not sending from an exchange, rather do it via Geth or Mist since the gas will be calculated correctly for contract execution.