It took 31 years after being born, I finally made something that resembles a game. It's based off of Rampart.
http://gamogora.com/cc/cannons.jar (No webstart or applet, just a raw jar, I hope that's ok.)
Objective: Destroy the enemy fortresses before they destroy yours or have the most resources by the last round. Surround resources (trees, stone, hidden iron) with walls and place cannons and catapults inside your walls.
Controls: WASD to move through the menus, and space bar is select.
-It will probably crash or hang on displays with lower resolution (under 1024x768), so don't bother trying.
-There can be some major slowdown during build phases with the maximum number of players due to an inefficient algorithm.
-Even though the game is supposed to finish when you destroy the last enemy fortress, I think I didn't get to write that part, so the game will probably continue to play until the last round.
-Sometimes enemies don't build walls properly due to proximity to resources.