The Houston Symphony will kick the Halloween season off in style with a haunting evening of plaza trick-or-treating, ghoulish games, spooky songs, and a cacophony of costumes. Guests are encouraged to dress up in their Halloween costume for a chance to walk on stage during the concert. The first 100 boys and girls to check in at Hocus Pocus Central in the North Plaza, fully costumed, get the chance to march in the Goblin Parade.