At one of our quilt guild meetings, we had experienced members give mini workshops on whatever technique they had expertise. Several workshops were going on concurrently, each at a big round table. The guild members were divided into groups of about 10-12 to attend the mini workshops, rotating to a different table about every 15-20 minutes. So, everyone had a chance to attend every mini-workshop.
Actually, some of our workshops were not directly quilt-related (e.g., making rag rugs, fabric Christmas ornaments, etc.) However, your guild members can decide on which workshops they would like.
This was really a fun activity and worked also as a mixer to get folks to sit with different members than they usually sit with at guild meetings.
Another suggestion: We also have an annual sew-in to make charity quilts. Usually we collect charity blocks all year long, then at the sew-in we divide up into teams and make assembly line quilts. Our goal this year is to make 50 quilts.