Current events
The Ship for Preload
26 Jun: The Ship (Source), eagerly awaited by many, has been made available for purchase and pre-load on Steam. See the store page for more information.
SiN: Episodes Arena Mode
26 Jun: SiN Episodes Patch Released - Arena Mode Out Now! http://www.ritualistic.com/
Wikipedia updates
26 Jun: The Wikipedia article for the 
Source engine has recently undergone some large improvements. You may be interested in reading about some of the new technologies in development at Valve. As ever, feel free to make your own additions or corrections if you spot any errors!
Episode One
1 Jun: Half-Life 2: Episode One has been released
NightFall Returns
16 May: NightFall, one of the most anticipated Half Life 2 Mods, according to a recent poll on Interlopers has returned from its almost dead status. The mod has moved to a micro site of the Nigredo Studios commercial site at http://nightfall.nigredostudios.com
The mod has also announced Episode 1 that will be released very soon.
Atari back catalogue arriving on Steam
14 May: Most or all of Atari's PC back catalogue is to be made available through Steam as a part of their new GamersFirst budget range.