I'll give March of the Penguins a B+: it's a G-rated documentary, sometimes amazing, sometimes touching, about the family life of emperor penguins. It centers on their long trek from the Antarctic ocean to their inland mating grounds. After egg-laying, the females return to the ocean to feed, each leaving her male behind to keep their egg warm for months.
I described the idea to a co-worker, and she said, "I can understand that: you gotta go shoppin'!"
So what kept it from being an A?