Ah, but then there's the William Shatner avatar: Jason Nesmith (Tim Allen: The Santa Clause, Toy Story 2), who played Commander Peter Quincy Taggart, captain of the NSEA Protector. At Galaxy Quest Con 18, at which the film opens, Jason eats up the attention -- the fans love him "almost as much as he loves himself," his castmates note sardonically. And when a group of genuine extraterrestrials turns up at Jason's house later, asking for "Commander Taggart's" assistance... well, he freaks at first, of course, but then realizes this is an opportunity to be worshipped by his biggest fans.

Star Trek as religion: that's often the sneery, nonfan reaction to the Trek phenomenon. (And it's pretty close to the truth, though Trekism is a harmless faith: no one ever fought a war over whether Janeway or Sisko was the better captain. Well, not yet, at least.) But Jason's new alien friends really have adopted Galaxy Quest as doctrine. The Quest television transmissions they intercepted, as they tell Jason, transformed their culture from one lost and at war to one united and at peace. Like Star Trek, Galaxy Quest the series, never mind its trashiness, had at its heart an optimistic vision of humanity that rubbed off on the aliens.

The only thing is, the aliens think those transmissions were "historical documents." And now they need the great and brave Taggart to help in their defense against an enemy that threatens them. So Jason rounds up the rest of his "crew," and they get to work.

Galaxy Quest the movie is such a thrill for true fans of Trek and the like because while it does look a bit askance at fandom, it doesn't satirize fans and the objects of their adoration so much as celebrate them. When Jason and his fellow actors get a first look at the actual, full-size, genuine spaceship the aliens have built in replica of the TV show's cardboard model Protector, the sequence is a shot-for-shot take-off of the similar scene in Star Trek: The Motion Picture, that long, slow, lovemaking pan around the ship in dock. Yeah, it's funny as parody, but it also recognizes that we, the fans, are getting a kick out of it just as the characters are. Here, though, in Galaxy Quest, there's a whole other level of "buying into fantasy" going on. It's not the TV characters of Taggart and Madison and Lazarus with whom we're empathizing -- our empathy moves up a metalevel to share the excitement of the actors, Jason and Gwen and Alexander. They're fans at that moment, just as we are, believing in a reality that has previously only existed as make-believe TV. (And then, of course, we could move up another metalevel and talk about Tim and Sigourney and Alan, but that might make my head explode.)

The creators of Galaxy Quest get it. They get that it's a healthy obsession that drives fans of Star Trek, Babylon 5, Doctor Who, and even more obscure cultish TV series to lovingly catalog a show's every plotline, alien creature, and spaceship; to turn even bad actors into demigods; to see past wobbly sets and rubbery monsters to embrace an imaginary world. (To see just how much they get it, check out Travis Latke's Galaxy Quest Page, a hilariously dead-to-rights "fan site" for Galaxy Quest the departed TV show, complete with badly mangled photos, too many fonts, and a poorly written episode guide.) But they also get that fandom is a yin/yang kinda thing, a love/hate relationship, especially for cynical Xers: We'd like to totally buy into Star Trek or Doctor Who, but we're just too mocking to love unconditionally. So even though Galaxy Quest treats us to worshipful teens who live and breath Quest -- and have the technical expertise to help out "Taggart" in a pinch -- the filmmakers just can't resist throwing in the two twentysomething fans, whom Jason overhears in the convention's public restroom, snickering about how Jason doesn't know what a laughingstock he is.

The ETs are the ultimate fans, though, having altered their entire society for the better because of Galaxy Quest, and though the movie has some surprising resonance thanks to their purity and pathos, Galaxy Quest is mostly just pretty darn funny. The conventions of Star Trek-- er, I mean, Galaxy Quest get sent up lovingly: every cliché from lizards as bad guys to exploding computer panels is here. Sam Rockwell steals every scene he's in (as he also does in The Green Mile) as a two-bit actor and big-time Questerian who inadvertently joins the actors in their "mission" -- he's afraid he's the no-name extra playing the expendable crewman, a role that's a veritable death warrant. Tony Shalhoub (The Siege, The Imposters) does a deadpan caricature of Scotty -- laid-back and utterly imperturbable, he's the Trek engineer's polar opposite. And just as nice as it is to see Sigourney Weaver play against type is the reference to Aliens she gets in one line.

Just as those who don't understand the appeal of Star Trek will never get it, the charm of Galaxy Quest is probably limited to those of us already within the geek realm. So what? It's one more bit of fun we'll hog for ourselves.