SpaceRef Almanac  
   A broad source of space-flight information - daily updates, calendar of events, directory of space-related sites, discussion fora, and gateways to space science and astrobiology and the 'Whole Mars Catalog'. A service of Discovery.com.
   http://www.spaceref.com/

StarDate  
   Plan your backyard stargazing with the celestial information gleaned from this web.
   http://stardate.org/

Leonardo Almanac  
   Collection of technology reference resources and statistics.
   http://mitpress2.mit.edu/e-journals/LEA/LEA2002/LEA/index.htm

Handy Facts  
   A collection of handy facts about math, words, dimensions, space, and lots of useful and hard-to-find data.
   http://www.handyfacts.com/