Ancil and I met a pretty interesting guy, Elliott Felix, from Brightspot, who is involved in some way with the NC State project around the design of learning spaces. His slides are available here:
Note the shot of the Vitale Media Lab in Weigle Info Commons–is it Jesse??
Slide #6 has a nice list of activities you might want to support in a learning commons. To go one step further, one might think about the learning to be fostered in these activities and make that (and not the activity) the core of your design ideas.