Signal Strength
"Amelia Marzec, 30, displays her creation called Signal Strength. The hack involves using a device to send peer-to-peer signals between mobile phones, making a traditional network unnecessary and preventing conversations from being surreptitiously monitored."
Check the Occupennial calendar for details on when Marzec will set this up again. Stay tuned!
http://www.wired.com/rawfile/2011/10/political-hackathon/?pid=1210