Their show was cancelled 18 years ago, but the crew of the NSEA Protector is still in uniform, touring the convention circuit and pandering to fans who can recite every word of cringe-inducing dialogue they ever spoke. Sound familiar? You don't have to be a Trek weenie to have a good time at this spoof cum homage to fandom and the enduring appeal of cheesy TV, but it helps. Jason Nesmith (Tim Allen), who played pompous Captain Peter Quincy Taggart on "Galaxy Quest," is an even bigger jerk offscreen; fans love him, his fellow cast members would love to see him take a long walk off a short convention stage. Gwen DeMarco (Sigourney Weaver) was communications officer Tawny Madison, who existed solely to fill out her form-fitting space suit. Alexander Dane (Alan Rickman) once wowed theater-goers in Richard III, but achieved dubious immortality as Galaxy Quest's token alien, Dr. Lazarus. Having nicely skewered the convention scene, the movie kicks in with its central conceit: an especially odd group of costumed fans turn out to be bona fide aliens, Termians from the Klatu Nebula who've patterned their entire culture on "Galaxy Quest" reruns. Now they're under attack by vicious alien warmonger Sarris (Robin Sachs) and are convinced that only Taggart and his crew can save them. Screenwriters David Howard and Robert Gordon have a blast pitting the fake space cowboys against everything from cutie-pie aliens with vicious fangs to a machine composed of pounding pistons whose only apparent purpose is to imperil Nesmith and DeMarco. "That episode was badly written!" she howls, when it's pointed out that just such a contraption once figured in a "Galaxy Quest" episode. And Sam Rockwell has a fine time as goofball Guy Fleegman, who worries about the implications of his "Galaxy Quest" experience, which consisted of getting killed before the first commercial.