OSDev.org

Have a read: http://en.wikipedia.org/wiki/Mark_V_Shaney Ingenious for it's time, and the way it works is fairly simple too.

Emergent behaviour is fun. I once coded an IRC bot people thought intelligent because it responded to natural language.

In fact, all I did was look for two keywords, then pop out the string between them as being the "argument" to the function called. Artificial Intelligence in two lines of VB code, woot (and heuristics FTW too)