See http://www.courseforum.com.

This is a commercial web application developed by [Mark Roseman],
which was briefly described during Mark's keynote at the [Ninth Annual Tcl/Tk Conference].

Think of it as a cross between a Wiki environment and a discussion group, 
but targeted specifically at educational users.  Lots of advanced features but
emphasizing ease of use and ease of deployment.  

Based on Tcl, incr Tcl, MetaKit, StarKit, procomp, etc. etc. etc. etc.