SELL OUT WITH SONG: It's a concert, a dance revue, a comedy act! It's this year's Spectrum show at Gaither High School. About 70 students are staging the money-themed performance called "Sells Out." It will be the next-to-last production under longtime Gaither choir director Jerry Skora, who is retiring this year. "Sells Out" is at 7:30 tonight at the Gaither auditorium, 16200 N Dale Mabry Highway. Tickets are $4 at the box office, but the show may be sold out. Call 975-7340 for information.