Dead Island: Official site. Includes news, screenshots, movies, files, and a forum

Descent2.com: Provides related content. Also contains Descent 1 content

Doomworld: Provides news and information about the games and add-ons for them. Also hosts Doom related projects, discussion forums, and collected utilities and source ports

Fanatic's Asylum: Various add-ons including New Breed, Breed DM, ROKS, and the QDoom TC

Kali: A multiplayer gaming service allowing Descent 1 and 2 play over the net