Quite a while back, while I was surfing for "fun" bits of information to be included in some course notes, I came across this e-book version of Hal's Legacy.
Hal (or more formally, Hal-9000), as you might recall, is the supercomputer in the science fiction book/movie classic 2001: A Space Odyssey who (yes, I insist, who) eventually committed murder in an endeavor of self-preservation. Hal's Legacy is a great book for students interested in artificial intelligence, natural language processing, robotics, or just geeks in general. And it's online in its entirety for free!
Enjoy!