Day of Defeat: Official site for the WWII Half-Life mod. Contains news, updates, downloads, and forums

halo.bungie.org: Community site with the latest news, forums, comics, fan art, Bungie exclusives

Haze: Official site. News, key features, videos, screenshots, artwork, downloads, and forums

HereticII.com: Offers news, FAQ, guide, interviews, tutorials, and links

Hitman: Blood Money: Official site. Game information, characters, trailers, screenshots, and downloads

Planet Half-Life: Resource includes files, forums, modifications, articles, and daily news

Unknown Worlds: Natural Selection: The official home for the multiplayer sci-fi Half-life mod, Natural Selection