I don't know how to put it in english (I'm from Brazil
), so if you cannot understand it right from the first time, you can blame me. There's an Internet Chess Club (they play by email) that is running some sort of king of the hill kind of tournament (they call it pyramid chess). The rules are:
1. Anybody can join at any time.
2. You start at last position, and can challenge someone that has a better position than you.
3. Challenger get's black, defender get's white.
4. If you defeat the defender, you get his position (so, winning against top player makes you the top player), and he is pushed one position to bottom (as it turns, everybody that is between you and the challenger is pushed one position down this case).
5. If you fail to defeat the defender (either by a draw or by loosing the game), then you cannot challenge him again in your next game, you must choose someone else.
You can put some records, as who is in the 10/100/1000 top players for more time, who is the top player for most time, who is the better defender, who is the better challenger, and so on. To avoit top players being overhelmed by challengers, you can put some kind of limit in the distance you are and the player you can challenge, for example - maybe you cannot challenge anybody that is 100 positions far from you -, and anybody that has 20 games cannot be challenged for any more game, until some game is finished, and nobody can place more than one (or another number) challenge at time.
That's only an idea, I hope you like it...