American historical documents sources: Amdocs (transcriptions), OurDocuments (facsimilies and transcriptions)
FindLaw - includes databases of federal, state, and local laws and lots more.
How Stuff Works - explains the operation of a wide range of things.
HyperHistory Online - Time lines of people, historical periods, and events over the last 3,000 years.
Internet Movie Database - comprehensive information about 170,000 movies
Internet Public Library - Contains a wide variety of reference materials.
Kelley Blue Book - pricing and availability of new and used cars
WebElements.Com - Chemistry site including the first periodic table on the web.
World Factbook - information on the countries of the world
Zip Code Demographics - census data by zip code