Thank you. Dark Winter...
Here's an interesting link to the National Memorial Institute for the Prevention of Terror:
http://www.mipt.org/darkwinter06222001.asp
The linked article provides further details on the "Dark Winter" wargame simulation. The MIPT was one of the participants, along with Center for Strategic and International Studies, the Johns Hopkins Center for Civilian Biodefense Studies, the ANSER Institute for Homeland Security.