Portal 2, a new game from the Valve Corporation, makes physics fun.

You are a woman trapped in the distant future in an abandoned robot factory buried miles beneath the Midwestern plains. The only other characters you encounter are two deranged artificial intelligences vying for control of the complex.

You must escape to the surface. And this requires navigating a series of meticulously designed test chambers that the robots have devised to measure human intelligence.

To achieve your escape, you use a “portal gun” to blast open portals while learning some physics. For example, the conservation of momentum: when you enter one portal, you emerge from the corresponding portal at exactly the same speed. This means that gravity becomes your personal propulsion system.

Portal 2 was released recently for Windows, Mac OS, Xbox 360, and PlayStation 3.