This 13-minute video is highly recommended as a glimpse of what can be done when data are open and our computational power is shared: http://www.wolframalpha.com/screencast/introducingwolframalpha.html.
Highlights: type in 5 miles per minute and almost instantly have a list of useful and interesting conversion information; type in france fish production and quickly find out the total fish production per year in France - and that it is 1/5 of the annual trash production of New York!
See also Peter Suber's post on this topic on Open Access News.
