Dude, as if I would ever be bored with Half Life 2, valve went and released Half-Life 2: Episode 1. This extension to the original HL2 game takes place shortly after the end scene of the single player game. It came out on June 1st, but I was working late so I couldnt get to it. But I downloaded it today (the 2nd) and played it straight through.
In all it took me about 6 hours to complete it. I was slightly (and only very slightly) disappointed that my $20 only bought me so much game, but I think overall it was worth it. After all, I can always play it again. 
Other than that, it was as freaking awesome as the parent game and made more so since it continued the story line from the originals ending. Valve plans to make 2 more extensions (Episodes 2 and 3) that will be available probably in the next 6 months or so since they said that the series will be completed by Christmas 2007. I, personally, can hardly wait.
On a side note, I wish they would remake Team Fortress Classic. That game would kick so much ass run under the HL2 engine. Maybe I should write an email to Valve and ask…
Anyways, if anyone is interested, here is the link to the new episode on Steam Powered
Cheers