Helpful (http://helpful.io). Ruby on Rails helpdesk software trying to make things like ZenDesk & Desk.com suck less. Github: https://github.com/asm-helpful/helpful-web. There is always a list of things to do (https://assemblymade.com/helpful/wips) and a community around to help. We also share the ownership (and profit) of the app between the contributors. Anybody is welcome to be "Helpful" and join in building it.
Full disclosure, founder