Wolfram Alpha…
Stephen Wolfram is a lot of things. The common threads would have to be mathematics and genius. Here’s his wikipedia entry. His main claim to fame is Mathematica, a piece of software that can do just about any math computation you can throw at it.
Wolfram’s latest project is Wolfram Alpha, a search engine that combines natural language processing with expert guidance over a limited search domain. In plain english, ask Wolfram Alpha your question and, if it happens to have a good data source on that particular topic, it will present a customizable framework that answers that question.
Wolfram Alpha excels at any question that allows or requires computation. You can type 2+2, that sort of thing, but that’s too easy. Here’s a bit of introductory calculus:

There’s not a better mathematical resource available, and Wolfram Alpha is free.
What else can it do? Lots! For starters, take a look at this short video. Or, go to the site and type in your own queries. For example, try “gdp of france” or “melting point of copper” (quotes not necessary). There is a bit of a learning curve you’ll have to bust your way through but, if Wolfram Alpha knows about your search domain, it becomes an incredible resource.
– Dave
