The First Annual Brooklyn Mustard Festival is happening Saturday, April 28th, in the beer garden at T.B.D. Bar in Greenpoint, Brooklyn from 12-5. It will be a celebration of mustard in all of its pungency and richness, its nobility and sloppiness. A smattering of vendors — mostly local but some distant — will be offering up an array of mustards and mustard-based delicacies.