Source: HalfLife2.net
Related: YouTube - Part One
Related: YouTube - Part Two
Related: YouTube - Part Three
This has to be one of the best things I have seen from any game company for the hearing impaired and actually opens my eyes to a population that loves video games but only get a limited experience. Something that I have been seeing more and more of for PC games is tactile feedback to augment sound effects. This is brought up at the end of video 1. Check out the videos for yourself.

A young gamer who is deaf went to Valve for a tour. Gabe took the time to sit down with them. Watch the videos and be amazed. At one point they tell Gabe that he should add a feature into gaming so that deaf users could tell others as they are playing. The main thing you get from these videos is Valve cares about the gamer and the community.

Part One
Part Two
Part Three