To watch Jon Brion onstage is to watch a mad-scientist genius devise his best potion.

Brion has produced and arranged tracks and albums for Tom Petty, Fiona Apple and the late Elliott Smith (including Smith's posthumous album). On his own, he plays a completely different show one Friday night per month, taking audience suggestions as he sputters about the small Largo stage, testing instruments, tuning up and looping drums, synths, guitars and toy saxophones to make full-band arrangements of the songs that the audience challenges him to play. He swings from Cole Porter to The White Stripes to The Beatles to his own heartfelt compositions, which he lovingly calls "unpopular pop." Unpopular? Maybe. Brilliant? No doubt. Reservations are required to reserve a seat (there's a two-drink minimum). Door cover is $15 (cash only) for standing room by the bar, and there's a two-drink minimum. Hush! Listen!