Members of the Grateful Dead are coming back to life in a new supergroup with John Mayer. Mickey Hart, Bill Kreutzmann and Bob Weir have joined with Mayer to form the band Dead & Company. They will perform Oct. 31 at New York's Madison Square Garden. The Dead reunited this summer for a Fare Thee Well tour that included five shows celebrating their 50th anniversary. Tickets for the Halloween show will go on sale August 14th. A press release Wednesday said top-tier tickets will be priced under $100, while $50 tickets will be available in honor of the Dead's 50th anniversary.