For a while there was a wiki at http://github.com/kylemcdonald/artsec but it was never really used, so I removed it. The leftovers are below.
Physical displays in NYC - subverting what is displayed. Requires hardware access, possibly proper watermarking. What content is appropriate?
Network subterfuge - playing with assumptions on mobile networks. Spoofing GPS or access point data to fool location aware devices. Unintentional Flash Mob?
Spoofing known Access Points, using Man in the Middle to do fun things, like take over coffee shop networks, make people speak to one another.