A fun one would be PNZ: PoNZicoin.
It uses proof of stake, but you get 1% per day instead of 1% per year...
-MarkM-
Actually that's a great idea: a cryptocoin based on sponsorship.
You are someone's sponsor when you are the first one to send money to their address.
After that, you'll get a cut of everything that transits through this address, and your own sponsors will get a cut of your cut and so on.
Or maybe sponsors share the fees instead of the minors. Or both get fees.
Or even better: later comers pay more fees.
Let's do it!