Wolfram|Alpha

If you haven’t already been, I recommend checking out the Wolfram|Alpha “computational knowledge engine.” It is, of course, making headlines as a “Google killer.” While I doubt that, it is pretty fun and elegant.

“Wolfram|Alpha's long-term goal is to make all systematic knowledge immediately computable and accessible to everyone. We aim to collect and curate all objective data; implement every known model, method, and algorithm; and make it possible to compute whatever can be computed about anything. Our goal is to build on the achievements of science and other systematizations of knowledge to provide a single source that can be relied on by everyone for definitive answers to factual queries.”

http://www.wolframalpha.com/