Just a few little headlines over the last week or so:
Garry's Mod version 8 has been released and is the best version yet. Loads of superb new features, check that out here.
DaikenTana from Garry's Mod forums has posted some renders of HL2 models with real HDR Lighting, they look incredible. Make sure you check them out in this thread.
DaveJ is apparently re-working another Dust level, to combine the best of Dust and Dust2. It will be released with PCGamer UK, full details and screenshots can be found on Dave's Blog.
Finally, some info on the "Lost Coast" HDR lighting level. Gary McTaggart, a Senior Software Engineer for Valve Software has let slip some info regarding different detail settings. Read that here.