Valve has announced that the Crash Course downloadable content for Left 4 Dead will be released for PC and Xbox 360 on 29th September.
Elsewhere, Joystiq reports that Valve's Kim Swift announced a 27th October demo release date for Left 4 Dead 2 during an EA press conference in Tokyo, although specifics were not discussed.
In yet more Left 4 Dead news, the developer also issued an Xbox 360 patch yesterday that introduces elements like the special infected HUD tweaks showing team-mates' recharge times.
That's presumably so that people who choose not to download Crash Course still have parity with the people who do when they come together on other campaigns.
Valve hasn't said anything about whether that's a bug yet, but we should find out by this time next week.
Crash Course bridges the gap between the No Mercy and Death Toll campaigns in the original game, and has been designed for shorter, 30-minute Versus mode games, as matches using the existing campaigns can take around two hours to complete.
Look out for our review of Crash Course around release. It's free on PC and 560 Microsoft Points (£4.76 / €6.72) on Xbox 360, something Valve explained to us recently.