Plympton also said that all of the short nominations are "computer films." I'm not sure if that's accurate. Teddy Newton's "Day and Night's" characters are—according to this explanation—2-D animation with 3-D animation existing inside of them that reflects the characters's emotions. This video gives an explanation.
Based on the clips I've seen of this film—and the Academy's alleged preferences for both West Coast animators and 3-D animation—I believe Newton will walk away with the Oscar. I'm also intrigued by the idea of this film and its execution and look forward to seeing it in its entirety (haven't seen Toy Story 3.)
The only other short film I have any familiarity with is "Madagascar, A Journey Diary." I saw this still from the film that blew me away. I've also seen scenes of the film and it not only looks like a watercolored travel diary but it includes some great technical shots. I can definitely see why this was nominated.
After a quick search, I found the film for download here. This is surprising because I thought films online were ineligible for Oscar consideration. Plympton said his "Santa: The Fascist Years" —one of his recent best films, I think—wasn't eligible for Oscar consideration when it was completed.
The other short nominations:
"The Lost Thing"
Best of luck to all of the nominees!