As I learn more about Computer Science, AI, and Neural Networks, I am continually amazed by the cool things a computer can do and learn. I've been fascinated by projects new and old, and I'm curios of the interesting projects/applications other SO users have run into.
http://alice.pandorabots.com/ - This bot is able to have pretty intelligent conversation with us.
One of my own favorites is Donald Michie's 1960, Project: MENACE - Matchbox Educable Naughts and Crosses Engine. In this project Michie used a collection of matchboxes with colored beads that he taught to play Tic-Tac-Toe. This was to demonstrate that machines could in some sense learn from their previous successes and failures.
More information as well as a computer simulation of the experiment are here: http://www.adit.co.uk/html/menace_simulation.html
The Numenta Platform for Intelligent Computing. They are implementing the type of neuron described in "On Intelligence" by Jeff Hawkins. For an idea of the significance, they are working on software neurons that can visually recognize objects in about 200 steps instead of the thousands and thousands necessary now.
Edit: Apparently version 1.6.1 of the SDK is available now. Exciting times for learning software!!
This isn't AI itself, but OpenCyc (and probably it's commercial big brother, Cyc) could provide the "common sense" AI applications need to really understand the world in which they exist.
For example, Cyc could provide the enough general knowledge that it could begin to "read" and reason about encyclopedic content such as Wikipedia, or surf the "Semantic Web" acting as an agent to develop some domain-specific knowledge base.
w:
Arthur L. Samuel (1901 – July 29, 1990) was a pioneer in the field of computer gaming and artificial intelligence. The Samuel Checkers-playing Program appears to be the world's first self-learning program...
Samuel designed various mechanisms by which his program could become better. In what he called rote learning, the program remembered every position it had already seen, along with the terminal value of the reward function. This technique effectively extended the search depth at each of these positions. Samuel's later programs reevaluated the reward function based on input professional games. He also had it play thousands of games against itself as another way of learning. With all of this work, Samuel’s program reached a respectable amateur status, and was the first to play any board game at this high of level.
Samuel: Some Studies in Machine Learning Using the Game of Checkers (21 page pdf file). Singularity is near! :)
http://www.triumphpc.com/johnlennon/
recreating the personality and thoughts of John Lennon.. you can have a chat with him on this site.