History of Electronic Publishing: An interactive history of videotex and teletext projects in various countries during the 1970s and 80s, created by Bill Johnstone and David Carlson.
IRS Digital Daily: Searchable site filled with tax codes, federal income tax information.
FECinfo: Federal election information from independent source; campaign contributions by zip code.
Common Cause: Congressional voting records; soft money political donors, etc.
The Center for Responsive Politics: Another site for voting records, campaign contributions; profiles of congressfolk.