Susan, that's an amazing list of resources!  I can add one more, 
www.Maplight.org, which tracks campaign contributions in Congress (and the 
California legislature) along almost any dimension you can think of.  You 
can find more information about Maplight and a lesson plan for using it, as 
well as many other articles and activities math and otherwise, in the 
current issue of The Change Agent, "Democracy in Action," 
http://www.nelrc.org/changeagent/toc.htm.  Our own (on this list) Cynthia 
Peters was the editor and I was privileged to be one of the contributors. 
It contains a lot of ways to think critically about democracy!

Wendy Quinones