Stop thinking about the phone as a phone, and start thinking of it as an Internet device. Don’t try to reproduce the PSTN on a VoIP system, throw away your concepts of what a phone can or can’t do, and think about what would be a cool way to communicate through some kind of handheld, desk-mounted, or ethereal device. Maybe your idea ties into a game or into bringing someone who is located in another region on Earth into your space through an enhanced form of contact. We don’t know what the next killer application will be; however, it is just as likely to be born out of an accident or for an individual’s convenience as designed in a professional research laboratory. We’d like to think that with the tools available on the Internet, along with open source software, that our future will be made better through the creativity of scattered individuals.