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.
“Say this for big league baseball - it is beyond any question the greatest conversation piece ever invented in America.”
“Getting close to books, and spending time by myself, I was obliged to think about things I would never have thought about if I was busy romping around with a brother and sister.”