3D Realms - The masterminds that are behind Duke Nukem 3D
Planetduke.com - Gamespy site containing tons of stuff related to Duke3D
Duke Nukem Repository - Simply the best place to look for custom Duke3D maps, addons and utilities
ProAsm's Homepage - ProAsm hosts his own Duke3D port, a launcher utility and many conversions
Birger's WinROTT Site - B. Andreasen and J. Stafford made cool Win32/OpenGL ports for Apogee's classic "Rise Of The Triad"
Dark Forces for Jedi Academy - Great mod for "Jedi Academy" that lets you play "Dark Forces" again. Try the demo if you can!
Jedi Knight for Jedi Academy - A few crazy guys have gathered, trying to resurrect "Jedi Knight" with the "Jedi Academy" engine
Bloodmasters - Experience this old-school top-down shooter via LAN or online. Needs .NET Framework 2.0, but it's freeware!
Jets'n'Guns - Very cool arcade space shooter sidescroller, extremely addictive. Has won many awards - you should find out why!
Knee-Deep In ZDoom - Amazing recreation of first DOOM episode for ZDoom/GZDoom ports. Huge, detailed levels, new monsters and weapons.
World of Padman: Standalone Complex - Standalone Quake3 mod by ENTE letting you play in a comic-style miniature environment. Excellent!
JFDuke3D - Jonathon Fowler's Duke3D Port
EDuke32 - An enhanced, heavily modified version of JFDuke3D by TerminX. Recommended!
Duke3D HRP - Duke3D High-Resolution Pack (*MUST-HAVE*!)
Mark McWane's Music - MP3/OGG renderings of the Duke3D MIDIs
Mark Knight's Game Sounds - Mark's a great composer for video games soundtracks. He did a cool recreation of Duke3D Playstation soundtrack!