If you have a Quicktime plugin, check this one out: Over Time. As far as I can figure out, it's an operatic representation of what the Muppets did the day Jim Henson died. Quite beautiful.
Another favorite CGI animation is The Cathedral, which somehow lost the Short Animated Film Oscar at the 75th Academy Awards to the insipid The Chubchubs. Well, actually, it's obvious why a beautiful work of art made by unknowns from Poland would lose to a cute, topical cartoon with dancing aliens from Sony Pictures' Imageworks (damn my cynicism.)
As long as I'm cynically plugging short animated film Oscar losers, you might want to also check out Fifty Percent Gray (though I do like that year's winner For the Birds by Pixar, so I'm not begrudging anything. This time.)