Last year our quilt guild had the theme of "Reduce, Recycle", and it was great fun! We had a fabric exchange at one meeting which didn't reduce our stashes, but allowed us to get rid of fabric we didn't have a use for and acquire some that would help in finishing current projects. At the beginning of the year people reported a list of their UFO's, and then at each meeting checked off anything they had finished. Each UFO finished became an entry in a drawing at the end of the year.
Of course, we still all bought some fabric throughout the year, but the theme and encouragement from each other helped remind us of the goal of using our stash.
Dayle