roundtable.audio is an open-source web app which enables real-time audio discussions. Users can generate public or private ad-hoc "roundtables", or create them via other sources on the internet (currently supports Twitter and Hacker News).
Mantis is a live-audio chat widget which can be embedded into any website with two lines of code. It's primarily intended for sales and support, and can be used to quickly answer site visitor questions and learn more about user needs.
