TechCrunch has some photos of a usability lab used by the Gmail team at Google. Some of the photos include earlier iterations of Google Chat that were being tested in the lab.

I only see shots of the observers' room in the photos, but there's some description of their testing room as well.

It’s a small room with a large flat screen monitor, along with a desk and computer. It also has a number of discrete cameras (and a microphone) that keep an eye on the user herself as well as the screen.

Around the corner is a second room where Google employees can watch people interact with the software real time. The room has a couch and a chair along with two screens and speakers to monitor the lab. See the image to the right.