This WebRTC telephony solution offers high quality audio. When I first posted about this in March [1], it was only possible for others to call me. Now everybody can register unique phone numbers and receive calls from anybody else. WebCall basically mimics a small telco now. You can use my WebCall server, or run your own. If you do this, please let others use your server as well. Traffic and load are really low. It is possible to host up to 30K concurrent users on a 1GB server. But you can also limit the number of users and run WebCall "on the side", like an e-mail server.
I will be here again at 21:00 Berlin (3pm NY) to answer any questions. In the meantime, why not register a (burner) phone number and post it so others can call you? You can always fetch a new phone number when you need one.
[1] https://news.ycombinator.com/item?id=26572925