> That's where I got my first taste of programming - writing a PID controller for a tank turret so I could point the tank's gun using my mouse.

Yeah, same here! I had done a couple of simple personal Flash games previously, but Garry's Mod is where I really felt like I cut my teeth on programming. Doing Wiremod/Expression 2 taught me PID controllers and some basic linear algebra, and after having helped some friends debug their code, taught me the importance of style and good practices.

Wiremod, that was it! What a blast from the past. Garry's Mod is probably the reason I have a career in programming now. That, and Minecraft redstone!