6. "Portal" (franchise)

Release date: October 9, 2007

Platform: PlayStation 3, Xbox 360

Buy it here.

You've never had so much fun solving puzzles. In "Portal," you wake up in a glass-enclosed room that's owned by Aperture Laboratories, which is running a series of "tests" on you. Your goal is to pass these tests with one tool and one tool only: a portal gun, which creates one blue and one orange portal. If you enter through the blue portal, you'll come out of the orange portal, and vice-versa. It's an extremely simple premise — best the tests, and escape the labs — but it's a highly enjoyable experience, marked by some of the funniest writing ever found in a video game as well as some of the most creative physics-related puzzles you've ever encountered.