most of you may be familiar with the '20q' game that is offered on 20q.net, which seems to be a rather generic neuralnet based expert system (not sure about the 'expert system' part). i seem to remember that it was originally programmed in perl, yet google doesn't help too much looking for it.
Does anybody know where i could find the source of something similar, preferrably with a big knowledgebase? AFAIK, the algorithms used are extremly generic, and could be used for a lot of fun stuff, but i forgot all everything my AI classes taught me, so i couldn't be able to program something like that from scratch.

thanks,
-schweini