The Activity Model:

Opening (Set a Goal):  A learning target to achieve; e.g., "We need a sales training program for the forthcoming model of our new widget.  What needs to be included?"

Middle (Group Work):  Small groups discuss the program needs and create reports.

Closing (Report and Discuss Findings):  Each group reports its findings.  The facilitator lists important issues, notes views as to their significance, creates a findings list, then prioritized as to their importance.

Cautionary Note:

The model described above is but one of many possibilities and... facilitation is difficult, it may be the most challenging of all speaking skills. If workshops are an important part of your speaking engagements I recommend studying the process carefully.