Updates to Counter-Strike: Source have been released.
The updates will be applied automatically when your Steam client is restarted.
The major changes include:

Counter-Strike: Source

    * Fixed new weapon firing integration causing some guns
      to over-fire on single taps
    * Fixed a couple of cases where machine guns could skip
      slightly with enough lag
    * Fixed c4 explosion pre-caching
    * Added precise audio timing fixes for client-side prediction
    * Increased the tolerance for skip detection in client side
      audio to prevent sound dropping out due to client clock drift
    * Completed work on clan tag strings validation

Updates to Counter-Strike: Source have been released.
The updates will be applied automatically when your Steam client is restarted.
The major changes include:

Counter-Strike: Source

Second half of 7/23 update

Updates to Left 4 Dead 2 have been released.
The updates will be applied automatically when your Steam client is restarted.
The major changes include:

Left 4 Dead 2
New mutation: Healthpackalypse!

Counter-Strike: Source:
- Fixed a crash that could occur after the bomb exploded.
- Fixed a crash that could occur when attempting to exit the game.
- Changed default values of the following server variables to reflect the increase of the
default tick rate from 33 to 66:
    - sv_mincmdrate - 10
    - sv_maxcmdrate - 66
    - sv_maxupdaterate - 66
- Marked 'developer' cvar as cheat.
- Corrected kill/death reporting in gun games.  Deaths were not being properly counted in
games using instant respawn.
- Marked test_round_winpanel, test_match_winpanel, test_freezepanel commands as cheats.
- Added sv_nowinpanel and cl_nowinpanel options that can be used to disable the win panel
that displays the team winner, MVP, and fun fact at the end of a round.
- Clamped ladder dampen values.
- Fixed jointeam cvar so giving it invalid values no longer spams the server console.
- Removed functionality of cl_minmodels.
- Fixed voice indicators to display at all times rather than just after their respective
players have come into contact when -alltalk is on.
- Fixed scoreboard to display correct number of SourceTV viewers.
- Adjusted death notices to display under scoreboard.
- Defaulted 'Simplified list' to OFF and made the setting persistent.
- Fixed an issue that could make it appear as if a player already had one or more MVP stars
upon joining a server.
- Made text on loading bar more legible.
- Added more materials that were missing for community maps.
 
Engine:
- Fixed disconnect exploit causing players to be forced off of a server due to
an overflowed packet.
- Fixed players being able to start the game using a DirectX level less than DirectX8.