Take a solidly built regular old telephone, mount it on a post (or in some sort of "phone booth" like thing) outside the office, with a sign that says "Call Anywhere for Free".
Phone is connected to our Asterisk service, and when picked up plays a recorded message:
"You can use this phone to make 5 minute calls to anywhere in the world. But we're going to record both ends of the call and make it available over the Internet for anyone to listen to. Think of this as public art, where you're the paint. If you agree to have your conversation recorded and made available freely on the Internet, press 1 to proceed."
Callers proceeding then get a dial tone that lets them make a call, via voice-over-IP, to anywhere in the world. The Asterisk server records the calls, converts the audio to MP3, and make available on the web, both on a website and as a "podcast feed."
The maximum VoicePulse Connect voice-over-IP rate for calls is $4.83/minute US for calls to "INMARSAT - Atlantic West". Price per minute goes down from there to $0.03/minute US for calls within Canada and the U.S.
Question: can participants call anywhere, or do we limit the calls to places with a certain price threshold?
There are 1440 minutes in a day. Maximum exposure at the US/Canada rate would be $43.20/day; a series of 5-minute INMARSAT calls would cost about $7000 a day.
Comment: Love this. Limit the the number of times a day that a specific phone number can be called, to one. I have access to a Danish phone booth like this one as TDC has a huge surplus (2000+) of these standing on a field north of Århus (wonder if I can find it on Google's satellite imagery...) ;) -- NikolajN
Do we need to know more about the callers to have them consent to recording and podcast -- their name? their age?