Late in Portal 2, you gain the assistance of a robot known as Rick the Adventure Sphere ("designed for danger"). It's a pretty heated moment, so the natural inclination is to swiftly complete the task at hand, but if you take your time, Rick says one great line after another, including singing an adventure song and suggesting catch phrases once you beat the boss. You can enjoy his dialog in the video above. And there's a brand new t-shirt design by up for vote at Threadless:
Finally, speaking of Portal, here's Erik Wolpaw's recent NYU lecture:
*Portal 2 is 40% off at Amazon.