On the marabou-feathered heels of the burlesque revival, sideshow performers are among vintage (or vintage-flavored) entertainers returning to the spotlight. A broad spectrum of acts ranging from comedic to grotesque appears at the Snake Oil Festival this week. In its second year, the fest is a primer on what are called circus, sideshow and variety arts. In addition to juggling and burlesque performances, there are more spine-chilling routines: "pain performance" artists who delight in being punctured and skewered, classic sideshow stunts like fire eating and glass walking, and suspension acts (imagine a person strung up on hooks, like a side of beef in a meat locker). Snake Oil's three showcases are organized by theme, though the prevailing emphasis of spectacle and showmanship promises eye-popping experiences nightly. For aspiring performers, daytime workshops cover topics such as stagecraft, glass walking and drag performance. Single-day and workshop tickets ($20-$50) are available on the festival website.