It appears that STS-126 astronaut Don Pettit had some spare time Sunday to resume his Saturday Morning Science experiments, which he conducted during his previous stay on the ISS back in 2002/2003. This time he demonstrated an improved version of the Zero-G Coffee Cup inspired by techniques used in liquid fuel tank designs.

You can find a video compilation of the very interesting Saturday Morning Science experiments here. By the way, did YouTube switch to HD during the weekend?