A while back I created a chat database to log conversations. Based on the context of the conversation it would find responses, so if ABC was said, it would search the database for ABCD and replies with D. If ABC is not in the database, it wil search for BC and finally C.
At first I thought I might use the database to start investigating chat bots for my master thesis, but that day never came. I've now used that database to bootstrap a new implementation of Wally at Google App Engine. I can now say that I've done something using the WebApp framework, and it seems to work. With the free quota it should be able to live a good and long life, so feel free to chat with Wally the echoing chat wall.