Half-Life 2

Like a musician who goes from the recording studio to the movie studio (we're looking at you, Ja Rule), video games usually take a step back when they go from the keyboard to the controller. But Half-Life 2 is the David Bowie of sci-fi first-person shooters, kicking just as much ass on Xbox as it does on PC. Of course, it helps that it's actually the same damned thing: same invigorating missions, same tight controls, same relentless action, and same trigger-happy scientist in a one-man war against our alien overlords. Just be careful, because before you know it, it'll be three days later, you'll have lost your job, your girl, and your pants, and you'll still want to keep playing.