It is one of the basic kids' fantasies: things coming to life when no one is watching, except - in this case - one bewildered bystander. And the idea of a museum where the exhibits suddenly become animated, is an interesting one - if not a new one. The trouble is in the execution. It can be a slippery slope applying any kind of logic to a scenario like this and to a certain extent you should just enjoy the zaniness and put your higher critical facilities in cold storage for the duration. But there is a point at which even the less critical facilities can't suspend their disbelief any longer: there is no internal logic to this movie. The script keeps throwing cool things at the viewer: little people, a doggie-minded T-Rex skeleton, historical wax figures, a bubblegum craving Easter Island statue, etcetera - but none of these elements have been very well thought out on their own, let alone all of them in combination.
There are some attempts to explain what is happening and why, but this only points out how much is not explained. For instance; how a couple of escaped Neanderthals ditched the camera-people that had spotted them and made their way back to the museum undetected. Instead of thinking small and coherent, the movie thinks big and creates a literal and conceptual mess in doing so. This is really a kiddie-movie, only for those adults who are prepared to shut down their brain to a dangerous degree, stopping just short of vegetable. Fairly ironic for a movie that wants to convey the message that learning about stuff is GOOD.
Ben Stiller does his usual lame-but-cool guy shtick and does it as well as ever. The movie wastes most of the big comedy names in the cast (Robin Williams, Dick van Dyke, Ricky Gervais and Mickey Rooney) as well as the potential love interest, who never quite gets around to being the actual love interest. Maybe in the sequel.
Night at the Museum at IMDB