Shona Whyte:
"Dakin Burdick, Center for Teaching Excellence, Endicott College, 2011, has this 9 page PDF describing ways of organising group discussions with large classes. Approximate time requirements are suggested, and formats and tools for online group discussion are also included. Concise, easy-to-follow, many ideas."
Via Dennis Richards, Phil Chappell, Shona Whyte