heres my latest brainstorm, feel free to critique: I call it Try 'n Call. Build a device that merges VoIP (voice over IP) and wardriving (using free open wireless network access points) and possibly a GPS to help that searching out a bit.
some embedded device that has 2+ wifi adapters, a GPS, and a line-in/out -> telephone adapter. This thing would sit in my car adn while i'm driving look for open access points. Upon connecting to one it sends my ID to a server (or group, or something) to let them know I am within a calling region. now that one antenna has a good lock, the other antenna searches for the next network so I can attempt to seamlessly transfer within my personal
yup.. I might just get 5 minutes of talk time on my way home!