Some are: www.
bigcharts.marketwatch.com (get stock quotes, info, any date)
savingsbonds.com (Treasury Direct--buy TBills without a bank or broker, Value Bonds)
usps.com (get zip codes and other info)
whitepages.com (includes reverse lookup)
bankrate.com (great financial info)
kbb.com (includes valuation of used as well as new vehicles)
GENERAL INTEREST:
pandora.radio.com (really fun to listen to)
jacquielawson.com (for $10 annually send friends very beautiful cards)
yourdiseaserisk.harvard.edu