Oh, that Jack Black is a hoot, even as an overweight panda who dreams of being a ninja. Some great lines from the beginning: "Legend tells of a legendary warrior whose Kung Fu skills were the stuff of legend.... It is said that his enemies would go blind from over-exposure to pure awesomeness!"
It's not all about Jack Black, though. His awesomeness is actually somewhat restrained and totally appropriate for kids. I liked this movie a lot, and I think the kids did, too.