If the kitchen fire that ravaged his Williamsburg restaurant, Brooklyn Star, last month took chef-owner Joaquin Baca by surprise, as fires often do, so too did the generosity and speed with which local businesses banded together to lend their support. Their joint effort, the Brooklyn Star Hootenanny, takes place Friday, March 26, at the Brooklyn Kitchen Labs, not with group folk singing, but with beer from Brooklyn Brewery, whiskey from Whiskey Town and Wilfie & Nell, smoked meats from the Meat Hook, Momofuku Milk Bar sweets, and Brooklyn Star’s own brisket and shrimp and grits. All that, plus oyster shucking and hot-dog-eating contests, and the chance to fell an aggressively whiskered Williamsburger in a 350-gallon dunk tank, for $50 in advance, $75 at the door.