PHPAdvocat (Anwaltskanzlei-Suite) is a web based office suite for lawyer offices to manage contacts, files/documents, invoices and events. It is written in PHP and stores data in a PostgreSQL or MySQL database. Though it is mainly designed for german offices it should be adoptable for other countries.
The Development has been moved to Gitlab: https://gitlab.com/phpadvocat/phpadvocat
CalDAV sync for Android
----
Stopped working on it. Doesn't make any sense to spend more time on it; I recommend e.g. DAVdroid as an opensource and ready-to-use solution on clientside.
----
For code look at:
https://github.com/e7o-de/android.caldav
Equipment/instrumentation booking and usage accounting system. Designed primarily for use in academic laboratories where a number of users share a set of instruments (e.g. NMR machines, microscopes, fume hoods).
Computer Repair CRM Open Source Project, A active web based customer management, trouble ticket and billing system for independent computer repair and service professionals and businesses based on the CiteCRM platform which ceased developement last year.