Useful links:

• MathSciNet via UIUC Proxy (requires valid NetID)
• MathSciNet search:
  Author Title Review Text Journal Institution Code Series Classification MR Number Reviewer Anywhere
  
• UC Davis front end for the xxx mathematics archive:
• LEO dictionary search:
• Google search:
• Dictionary.com:
  Dictionary Thesaurus
• UIUC Library Gateway
• Documentation of various scientific software packages at Columbia University.
• CompuTop.org: A site for the computational three-dimensional topology community.
• AMS Combined Membership List
• Geometry and Topology Address Book
• New York Group Theory Cooperative at CCNY
• Geometric Group Theory Page
• Geometry and Topology
• Cetus Links: Lots of links on Objects and Components
• DRK Lengerich: The Red Cross chapter of my hometown (I'm their webmaster)
• Become a member of the Electronic Frontier Foundation!

Just for fun:

• K-Chronicles
• Serge Gainsbourg: Bio and more
• Procol Harum: Beyond the Pale
• Galgenlieder by Christian Morgenstern, a part of the Projekt Gutenberg
• Mathematics Genealogy Project
• The Devil's Dictionary by Ambrose Bierce
• Slashdot.org: Stuff that matters