I have two ideas, I don't know if the second necessarily is CD but it'd be an interesting social experiment.
1. This summer I'm going to a double header at Fenway Park and my girlfriend and I will not be standing or removing our caps for the singing of the national anthem.
2. I found out about a site
http://chatroulette.com/ where you can cycle through various people's webcams. My friend put a stuffed monkey in his chair with a jar of vaseline and a wadded up tissue and watched people's reactions. I'm going to setup something anti state (I haven't figured out what yet) and gauge everyone's reactions.
Like I said, not really CD but it'd be fun to watch people get pissed.