“Monster House” is unpretentious, smartly written (by Dan Harmon, Rob Schrab and Pamela Pettler) and a lot of fun.

It also represents, to the technology nerds in the audience, an interesting refinement of animation techniques. Like Robert Zemeckis’s “Polar Express,” “Monster House” (for which Mr. Zemeckis served as an executive producer) uses the digitally captured movements of real actors rather than computer-generated algorithms as the basis for its animated images. The people in the movie look a little like molded-plastic figurines (the ones in “Polar Express” looked more like porcelain dolls), but their gestures are uncannily fluid and unpredictable, making you appreciate the quality of the acting more than you generally do in animated films. The postures and gestures of DJ (Mitchell Musso) and his pals — a pudgy fellow named Chowder (Sam Lerner) and a preppy redhead named Jenny (Spencer Locke) — have an authentically loose and antic look. They seem like real kids, rather than like super-cute, big-headed cartoon moppets.