If you were to imagine folk music made on a faraway planet called Aquatari -- where Sonar's Captain 69, Commander Colt 44, Commodore 64 and Doctor NC 17 claim to hail from -- you might expect a robotic kind of electronic music, with lots of erratic little Jetson-y space noises. In fact, the alien immigrants/Boulder residents, who perform Saturday, December 1, at the Fox Theatre, play the kind of jammy, funk-fortified, good-time music that their fellow Front Range players craft so well. Sporting alien masks and matching sci-fi gear, the band has a penchant for silliness that seems to comes naturally, as do its amusing, get-down grooves. Beginning in January 2002, the band will host a weekly series next door to the Fox at Tulagi. Saturday's show, then, should provide locals with a chance to preview the cosmically inflected collective that now shares their Zip code. Sonar may not be used to all of our human customs, but when it comes to the band's music, there's really nothing alien about it.