Symba is a Web-based framework designed to support collective activities in a learning context. In order to make students explicitly work out their organization it dissociates an "organizational level" and an "activity level" and allows students to describe their organization as plans composed of tasks.
Citation:
Marie-Laure Betbeder, Pierre Tchounikine, "Structuring Collective Activities with Tasks and Plans," icalt, pp.432, Third IEEE International Conference on Advanced Learning Technologies (ICALT'03), 2003