Being entertained by what you see in Night at the Museum: Battle of the Smithsonian is comparable to being entertained when you tell a retarded guy to get a can of polka dot paint and laughing your ass off when he comes back saying he can't find it. Only children could be excused for laughing at something like that in the same way that they are the only ones who can't be blamed for liking Night. Everyone else has no excuse.
Night once again follows Larry Daley (Ben Stiller) and his adventures with museum exhibits that magically come to life at night. Since we last saw him, Larry has left the museum and made a fortune making infomercials to sell crap. After not having visited the museum for months, he discovers that the exhibits are being transferred from New York to the Smithsonian Institute but the magic tablet that brings them to life will be staying in New York. This does not sit well with that damn monkey from the first movie who steals the tablet and ends up bringing back to life the Egyptian tyrant Kamunrah (Hank Azaria) who was on display at the Smithsonian.
One of the first things you learn about the Smithsonian in this is that some of the world's most famous and valuable artwork and exhibits on the planet are not guarded by things like alarms and motion detectors. Instead, the Smithsonian's entire security system is a few inept guards who, apparently, don't even work at night. This allows Kamunrah (Hank Azaria who got a few chuckles from me when I realized he was playing a mummy and was imitating Boris Karloff) and his new allies, Genghis Khan, Al Capone and Napoleon to move freely and launch their plans for world domination. Yeah, that's right, WORLD DOMINATION. These guys think that they and their small band of henchmen who can't even go out in the daytime since the tablet only works at night will take over the world. Kamunrah's plan seems to involve using an ancient spell to summon an army of Egyptian spirits. From what I saw, this "army" of birdmen armed with spears could be taken out by one guy with an M-16 but hey, what the hell? Sure, the world is in real danger of being taken over by Kamunrah.
Night isn't all bad. There's a funny scene with Stiller and Jonah Hill playing a douchebag security guard. There's also Amy Adams playing Amelia Earhart and looking damn cute while doing so. The problem with Night is a problem that all fantasy and science fiction must solve. You must suspend disbelief. You have to make the audience forget that what they're seeing is impossible. Night at the Museum has too many moments of stupidity, bad dialogue and characters who don't seem real even in this unreal world to achieve that with anyone but children whose standards for this are much lower. This is the polar opposite from Up which didn't make you think it was realistic, it just made you want it to be.
Not that they care about what I think, of course. this movie's made a bazillion dollars so far which means the next sequel will be pretty much the same when they go to someplace like the Louvre and Stiller teams up with a living Mona Lisa who will often exclaim, "Sweet Crepes Susette!" when she gets startled. Really, I'd bet money this will happen.