Heres an entry into the GBAX Coding Comp 2007.
Release from Alex Margarit
Sqdef is a tower defense game. The goal is to prevent enemies from getting from one side of the map to the other, by placing towers along their way. There are 9 different buildings, with upgrades, tech research, difficulty levels, and a whole lot of maps to try your defense skills on! It even has a secret tower!
Download Here
Screen Via Link Above and Help DIGG the Coding Comp