My little brother took part in the Google worldwide programming competition (or something like). Anyone can take part. The top 500 in the world get through to the next round. The top 250 get a tee-shirt. The top 50 get to go to California for the final round.
Him: But I don't get to go.
Me: Why not?
Him: Because I'm not 21. So at best I get a tee-shirt.
Me: That's not a very balanced incentive structure.
Him: It's a cool tee-shirt. It's got "Google" on it.
Postcript: And so it does.