Check this group out.
http://improveverywhere.com/

This is what I had intended when I founded Random Acts of Theatre (RATS) at Dakota Wesleyan back in 2000-2001. Student interest led the group to more traditional short-form improvistaion. I constantly find myself stuck between where I think a project go, and allowing students to follow their own creative impulses. Do I stifle them if I try to guide too much, or do I short change them by not pushing them far enough outside of their comfort zones?