From news.bbc.co.uk (via slashdot.org):

Researchers at Durham University have modified a video game and turned it into a fire drill simulator.

The team used The Source Engine, the 3D game engine used to drive Half-Life 2, and created a virtual model of one of the university’s departments.

Developers plan to use it to examine people’s behaviour in a fire and to train people in good fire practice.

Source