Travel blazer. I see this garment mentioned rarely around here. I stumbled across mine at Eddie Bauer several years ago. It was sulking, rumpled and forgotten on the deep clearance rack. It's lightweight, easy-care nylon and spandex, trés styley, festooned with interesting pockets, and is all but formless—no shoulder pads. There are many other travel and tech blazers, available in a wide range of prices and materials: Bluffworks, Wool & Prince, Wandertooth, Territory Ahead, and Orvis, all in the $200 to $300 range.
I use a small Eagle Creek folder to keep it presentable. Usually needs touching up with an iron once on each trip. It's an instant costume for fancy eating or if someone invites you to the opera.