Space

• International Space Station
• Encyclopaedia Astronautica
• The Solar System
• SETI@home: Search for Extraterrestrial Intelligence

Science & Technology

• US Government time service
• National Weather Service (USA)
• Periodic table of the elements
• Science Magazine online
• How Stuff Works
• "A Million RANDom Digits"
• The Long Now Foundation

Outdoors

• Globetrotter Outdoors Equipment
• Appalachian Trail Home Page
• REI Outdoors Equipment
• National Rifle Association
• Pennsylvania Hunting
• Geocaching
• Geohashing 8-)
• Ship's Captain's Medical Guide

Arts & Entertainment

• Projekt Gutenberg (DEU)
• Project Gutenberg (USA)
• Baen Books free science-fiction library and e-books on CD
• Ken Rockwell photography
• Dilbert
• XKCD
• Handy Latin Phrases
• Pandora Internet radio
• Yelping with Cormac

General World Reference

• Google Maps
• Google Translate
• EURODICAUTOM/IATE multi-language translation aid
• Webster's On-Line Dictionar & Thesaurus
• Wikipedia open-source encyclopaedia
• Encyclopaedia Britannica
• CIA World Factbook

Internet

• Google usenet news archive
• Better WhoIs internet domain lookup
• Electronic Frontier Foundation
• World Wide Web Consortium HTML Validator
• QR code generator

Software

• Google Earth virtual globe
• Skype Voice-over-Internet application
• GPGe ncryption software
• TrueCrypt encryption software
• SynchBack backup software
• Eraser secure file and disk wiper
• Picasa photo management
• Firefox web browser
• Calibre e-book management
• FileZilla FTP tool
• IrfanView image editor
• NoteTab text editor
• GhostView PostScript viewer and PDF generator
• CutePDF print-to-PDF tool
• Winamp MP3 player
• CDex CD ripper
• CSDiff file comparer
• Chicken Invaders arcade game ;-)