From a presentation here at CELDA in Cagliari. I've used the Jigsaw method myself without knowing it was called that (for my 'designing a PLE' workshops). Basically the idea is you have 'expert' groups that focus on a certain topic area, made up of members from groups from different disciplines. "The jigsaw classroom is a research-based cooperative learning technique invented and developed in the early 1970s by Elliot Aronson and his students at the University of Texas and the University of California. Since 1971, thousands of classrooms have used jigsaw with great success."