This is one of the funniest movies of the year, hilariously but affectionately skewering television sci-fi, its stars, and its fans. Not since William Shatner told Trekkers Dana Carvey and Jon Lovitz to “get a life” back on Saturday Night Live has there been such a sublime look at this world, reminding us, in these days of Adam Sandler and the Farrelly brothers, that intelligence and humor are not mutually exclusive. The fast, funny, and fresh script takes a terrific premise and unreels it in a tightly constructed farce that is filled with surprises. Perhaps the biggest one is that we really come to care about the characters.

Tim Allen, Alan Rickman, and Sigourney Weaver play former stars of a cheesy “Star Trek”-style show that ended nearly 20 years ago. Their only paying jobs are appearances at conventions of fans and store openings with their co-stars. A group of aliens who received the television transmissions of the program’s reruns and thought they were documentaries comes to Earth to ask for their help.

The TV stars find themselves on a real-life replica of their television series spaceship, lovingly constructed by the aliens to replicate every detail from the show. And they find themselves in a real-life confrontation with a lizard-looking tyrant named Sarris, trying hard to remember lines and plots from old episodes to help them defeat him.

The people behind this movie have watched a lot of Star Trek. Rickman, who played a character somewhere between Dr. McCoy and Mr. Spock, stares glumly at his alien gill make-up in the mirror and murmurs about the time he got five curtain calls as Richard III. Sam Rockwell (very far from his role earlier this month as the evil prisoner in “The Green Mile”) plays an extra who was killed on one episode, worries that he’ll be killed for real on this mission, because “my character is not important enough for a last name.” Tony Shaloub, as the Scottie equivalent tries to reassure him: “Maybe you’re the plucky comic relief!” The responsibility assigned to Sigourney Weaver, the Lt. Uhura equivalent, is repeating everything the computer says (and wearing a low-cut uniform).

After a string of slob comedies, it is a special joy to see one that is so sharply written and performed. Acting! Satire! Dialogue! Plot! I remember those! I’m just glad someone else does, too. If movies got curtain calls, I’d give this one five. (Be sure to check out the brilliantly designed “unofficial” website at http://www.galaxyquest.com/galaxyquest)

Parents should know that there is some cartoonish sci-fi violence, some of it rather gross, and one sad death, a character gets so drunk he passes out, and is then very hung over, and there are mild references to Allen’s character sleeping “with every Terakian slave girl and moon princess” on the show.