I'm not sure how old this is, but I just recently found it.
http://www29.wolframalpha.com/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.
Wolfram|Alpha aims to bring expert-level knowledge and capabilities to the broadest possible range of people—spanning all professions and education levels. Our goal is to accept completely free-form input, and to serve as a knowledge engine that generates powerful results and presents them with maximum clarity.
Wolfram|Alpha is an ambitious, long-term intellectual endeavor that we intend will deliver increasing capabilities over the years and decades to come. With a world-class team and participation from top outside experts in countless fields, our goal is to create something that will stand as a major milestone of 21st century intellectual achievement.
Basically, you can enter in a term, and it gathers loads of information about it. It lists some examples on the site. These include:
Dates: If you enter in a specific date (i.e. June 23, 1988), it shows how long ago that date was from today, major holidays on that day, major events that occured on that date, the moon phase on that date, and even sunrise and sunset times.
Cities: Entering in a city will bring up that city's location on a map, its population, the current time and weather, and its elevation above sea level.
Stocks: Enter in any number of stocks, and it will bring up latest trades and returns, price histories, performance comparisons, and projections for those stocks. It will display this information side by side for comparison if more than one stock is entered.
Calculations: Enter in any sort of calculation, and it will give you an exact result.
Mathematical formulae: Entering a formula will bring up graphs, alternate forms, roots, and much more.
These are just a few examples of what this website is capable of.
