The Reference Desk is a great resource for lots of interesting facts.  It has a good search capability.  http://www.refdesk.com

Information Please: On-Line Dictionary, Internet Encyclopedia, Atlas, & much more data.  http://www.infoplease.com

Library Spot: Encyclopedias, maps, online libraries, quotations, dictionaries and lots of other stuff at this site.  http://www.libraryspot.com

Biography: very interesting information to browse, print, or download.  An excellent learning and historical reference.  http://www.biography.com

How Stuff Works - Learn how tons of stuff works.  This site is loaded with fascinating information on everything under the sun.  Visit them at  http://www.howstuffworks.com The first time visitors may need to complete a simple registration form.