I was facilitating a session imagining our group were among the survivors of civilization's collapse 7 generations from now, with each of us improvisationally role-playing our great-great-great-great-great grandchild. I provided a story as a starting point, did some set-up (arranged Nancy White to do graphic facilitation; hired a face-painter to do tribal face painting to get us in the right frame) and launched the session with some simple questions.
The group got stuck in several places. Many couldn't relate to the scenario at all. Some were preoccupied with how we got to that future state and kept falling out of role.
Finally one of the participants, Juan Carlos (who happens to be one of the developers of the French translation of Group Works) jumped into the fray and modelled improv brilliantly. He invented some new words, described an invented situation in a moving and powerful way, and got the group into the feel of what it was attended to accomplish.
While the event was a modified success, it could have been much better if I had not made some assumptions about the readiness of the attendees for the activity, and their readiness to accept the scenario for the role-play as a realistic one. I should have done more research, and provided a better set-up (even if it took longer), perhaps even including a few pointers on improv. But I learned, we had fun, and I plan to do the session again.