Hey Kovu, what do you think of making things like actual gameplay part of customizing a map?

The default maps would have the generic behavior that you code, but perhaps other maps could use some sort of markup language to give it different gameplay.
Stat tracking and stuff could be encrypted on the client computers for player made maps, while the main uses a secure server database instead.
This would allow many different worlds with different game play and their own stats without placing a burden on the main server.

Obviously the markup language should have limited capability to prevent it from being a security risk to the clients or servers, but shouldn't be too limited.