I just wanted to give everyone an advisory here: if you weren't planning on seeing this movie, you should think about reconsidering. It was pretty god-damned entertaining.
If you have kids, they are sure to enjoy it.
Like a lot of Kung Fu movies, this film starts out with a loser who must train to defeat a dreaded enemy of the land. Like a lot of kids movies, the loser must first learn to believe in himself before he is able to vanquish the dreaded enemy of the land. The film centers around Po (voiced by Jack Black) and his deep love of Kung Fu leading to a most unlikely candidate as recipient of the Dragon Scroll which is supposed to turn him into the greatest warrior of the land. The man set to teach him, Shifu (voiced by Dustin Hoffman) has been teaching Kung Fu his whole life and finds no worth in him until he realizes that he doesn't really have a choice.
The two of them make a great comedic pair, better than I would have expected from a goofball like Jack Black (I mean that in a good way) and a classically trained bad-ass like Dustin Hoffman.
I would have to say that the film is perhaps the most mature 3D animated Dreamworks film the studio has ever made and certainly the only one worth watching (with the exception of their collaborations with Nick Park). And the best part of the movie? No shitty pop-culture references that will date the film.
The Kung Fu in the film is really, really fun and exciting to watch and will draw the kids in and was quite impressive. The 2d animated sequences of the film looked rad and the sound design was pretty good, too. One thing I enjoyed that Dr. Cyborg pointed out was that all of Po's action in the first half of the film before he learned Kung Fu was all taken straight out of the pages of classic Looney Tunes and it worked really well. Seeing anthropomorphic animals smashed by whipping trees, foiled by catapults and pole-vaults, cracked into walls and pounded into the ground is always entertaining to watch.
I'd read early on that Rob Schrab and Dan Harmon were the ones writing the script and that's why I was looking forward to it, but by the time the movie was finished, their names had been removed. I can't seem to find a reason for it, though I heard they were unhappy with Monster House, too, but that movie kicked a whole helluva lot of ass.
Long story short? It's a quick movie and worth the time and the price of a matinée ticket. If you've got kids, you should probably go see it now.