The Goblins, who established themselves in the 90s as Chicago’s finest purveyors of absurd conceptual garage rock, have been little heard from lately. Since 2001 they’ve done one gig where they played only J. Geils and Billy Joel songs and another where they paid tribute to T.S.O.L. while dressed up as Gong Show characters—and of course in 2006 they bravely and solidly backed Gary Burger of the Monks for a phenomenal set. But most of their scant handful of dates in the past decade have been kids’ shows. Tonight at the Bottom Lounge, however, the Goblins will be playing their own material for grown-ups in a rock club—something they haven’t done in nearly ten years—as part of the first night of their Caveman-a-Go-Go festival.