Eliza, the computer therapist...

ELIZA emulates a Rogerian psychotherapist.

ELIZA has almost no intelligence whatsoever, only tricks like string substitution and canned responses based on keywords.
Yet when the original ELIZA first appeared in the 60's, some people actually mistook her for human.
The illusion of intelligence works best, however, if you limit your conversation to talking about yourself and your life.

Talk to Eliza