At only 1:42, it's not exactly feature-length, but don't let the brevity of this clip put you off. It's about a brother and a sister telling you why they play, and enjoy, Minecraft. And it's wonderful.
The video was made by Britt McTammany, and it shows just why this game is so popular with kids. It's got nothing to do with survival horror. It's basically a newer, less expensive LEGO set.
Minecraft is Fun [Vimeo, via ALBOTAS]