If you log into Steam, you will download the newest patch for the Source Engine, which fixes quite a few nagging buggies, and adds a couple new things to the underlying engine itself. Not much else to say about this one, except of course to list some of the fixes:
Graphics:
- Fixed occasional graphics artifact tearing run running on Nvidia 6800 hardware
- Fixed mismatch of bumpmapped/non-bumpmapped surfaces in HDR
- Fixed bug where mat_colorcorrection wasn"t getting set properly on when running for the first time
- Updated default configuration settings for some newer video cards
- Fixed full-screen flicker bug when Alt-Tabbing out of fullscreen (particularly at high resolutions)
User Interface:
- Added progress bar state to print a description when the server changes levels
- Show disconnect dialog when client connection times out
- Fixed anti-aliasing on fonts
- Fixed a memory leak in vgui
- Fix for startup video not showing correctly if running fullscreen with desktop resolution less than or equal to 1024x768
- Fixed bug where game would crash when taking a bug screenshot if the screen/window resolution was wider that 2048 pixels
There are other fixes included as well, mostly to SourceTV and some for the Sound system. As always, just launch Steam and automagically you will get the patch. Long live content delivery systems!