This site says it has the information everyone should know, wants to know, or forgot. mistupid.com can test just what category you fit into. The resource section has a conversion chart to change measures like volume, distance, or weight (among others) between the different units of measurement. Looking for a new password? There's a password generator--select the parameters you need to generate a new password, but just don't forget it!
The features section has games to challenge your mind like a puzzle of the lower 48 states or one of the 43 Presidents. The table of contents is the place to go to find just about anything you could or would want to learn about, such as tutorials on different computer related topics, or something else like how to tie a tie or layers of the atmosphere or Morse code.