Casual Sparks fans can pinpoint their favorite Sparks period, and chances are, that period ended a long time ago. Most would pick the late 1970s to early ’80s, when Sparks’ founding siblings Ron and Russell Mael teamed up with Giorgio Moroder and released the space-disco classic No. 1 in Heaven and the synth-pop goldmine Terminal Jive. Rockists, though, would probably drift toward Sparks’ mid-1970s glam-rock peak—the time of 1974’s Kimono My House and Propaganda. (That would be my favorite if I were forced to forget 1982, when Sparks dropped the hilarious and anthem-choked Angst in My Pants.) But the mark of true Sparks fans is their taste for the band’s recent stuff. Oh God, Lil’ Beethoven, how I fail to understand your strangeness; and yes, I know 2009’s The Seduction of Ingmar Bergman is supposed to be brilliant, but I’ve listened to it exactly once—for research purposes—and that was sufficient for a lifetime. Now past their 40th year of making music together, Ron and Russell Mael transitioned from pop act to cult band long ago, and their faithful fans are special in one critical way: They don’t feel alienated when Sparks does weird stuff; some may even view it as a test of faith. So consider tonight’s show something of a musical bar exam. Only the most dedicated shall triumph. Sparks performs at 6 p.m. at 9:30 Club, 815 V St. NW. $25. (202) 265-0930. 930.com.