I've never read the book Generation Xbox, about video games invading Hollywood. Our columnist Superannuation (who's on a bit of a video game vs Hollywood run at the moment) has, though, and has found something interesting tucked away inside.
Seems that at one point, years ago, Valve (and its agents) met with both Sony Pictures and Dreamworks over the possibility of making a Half-Life movie.
According to Valve's agent at the time, Larry Shapiro, "the Valve kids' jaws [dropped]" when Steven Spielberg was present at the meeting with Dreamworks.
So where'd it all go wrong? Seems a few things, mostly that Valve didn't like what its share of the profits would be, and there were also disagreements over sequels and problems getting a production timetable together. You know, the usual stuff that kills video game movies.