My interest in Artificial Intelligence dates back to the time I saw SHRDLU perform on television (I think it was on PBS). This is a moment forever burned in my memory. Watching a person say "Pick up a big red block" then seeing a robotic arm understand and react to to the spoken phrase and manipulate its "block world" blew me away.

Check out: Terry Winograd's SHRDLU page for demo programs... be warned, many are fragile and don't do much if you phrase your commands incorrectly. See Conversation with SHRDLU for an  annotated version of a SHRDLU conversation.

Also note, the Java 3D version that has graphics, maxed out my CPU and was very fragile unless I followed the "sample conversation" word for word.

TRIVIA: The name SHRDLU comes from the phrase: ETAOIN SHRDLU which is the approximate order of frequency of the twelve most commonly used letters in the English language.