I have to say, I'm enjoying this server more than any other I've played so far. The players are reasonably mature, the world is tidy looking, and everyone I've met seems to be following the rules. The worst problem I've encountered is that occasionally I'll find a tree with the trunk knocked out. Recommended!
In-game name: Fractangle
Structures: My main SSP world consists of a bunch of 32x32 boxes of varying height that I dug out just above lava level, but some stuff I've built in other worlds in the past includes:
- A large Coliseum-style arena with a mob spawning room underneath that fed monsters into the arena via water elevators and canals (with obsidian floor to prevent creeper damage).
- Several semi-large (about 30 blocks high) tree houses.
- A number of dungeon-spawner-powered mob grinders.
- A (as an added bonus, it blows up whoever loses).
EDIT: What version is the server running? 1.7.3? 1.8.1? 1.9pr2?