freepbx - FreePBX is a web-based open source GUI that controls and manages Asterisk (PBX).
MINDBODY - Find and book fitness and beauty classes near you.
Asterisk - An open source telephony switching and private branch exchange service for Linux.
Kajabi - Kajabi is the only Knowledge Commerce platform today with everything you need to market, sell, and deliver your knowledge online.
FreeSWITCH - FreeSWITCH is an open-source media application designed to support popular protools such as SIP and WebRTC and provides a platform to develop voice and video applications.
Tendenci - Tendenci - The Open Source AMS is a cloud-based all-in-one management SaaS solution for Non-profits and Associations.