Often used by drunken residents of Worcester County, Massachusetts. Ta is an expression that is used to respond to a statement with the effect of "I wasn't listening to you and I don't really care about that." Originated at Rieatta Ranch Flea Market.
Person 1: "It rained cats and dogs here in Arizona today!"
Person 2: "Ta!"
Person 1: "mmkay.. have you been drinking again, Tituba?"