To anyone who's late to the party, you're missing out. Sorry for the later hour of this post, but I was busy eating cake... (well, I was actually busy between writing group and visiting a friend, so... same thing.)
Portal/Portal 2 makes up another of my favorite games. It's a fairly short game (first one, a student project, takes about 30 minutes. The single player part of 2 takes 6 hours or so.) but the 3D puzzles are highly satisfying, the dialogue is entertaining, and the story and characters are surprisingly complex. There's something so unique about flying through the air with a gun that doesn't shoot bullets, listening as a voice in the background promises you cake as it tries to kill you with turrets, lasers, and neurotoxin.
One of my favorite moments of the game, though, was finding a radio that played neither hidden transmissions or a certain jazzy theme. Instead, it played something that strangely, brought peace. It's called "Exile Vilify," and I sat and listened to the entire song before moving on.