Personally, I've found one of the more stimulating ways of playing in recent times has been to kind of move outside the free improvised area and work with people who are probably improvisers but they have a particular way of working.
Boxers, man, except when I have to get dressed up. Then it's boxer-briefs. But never tighty-whities. Never. But dude! If they brought back Underoos? Dude, if they brought back Underoos, I would rock the Underoos. Like He-Man and Transformers and G.I. Joe and even like Dukes of Hazzard.