I am going back to an old favorite today. Refdesk.com . You can find a link to just about anything on this page. Need to know gas prices by location - who knew there are about a dozen sites which you can explore. I just learned on this date in 1824 Beethoven's Ninth Symphony premiered.
It has links to the useful search engines, calculators, weather . . . I could go on and on. Great for a quick study break. Just be warned, you may get hooked.
Ernster, the Virtual Library Cat