Opark is an Android app for parking cars at the Opera office in Linköping. The app is published on Google Play at https://play.google.com/store/apps/details?id=se.barsk.park
Version 2 and later also connects to the Opark backend that is running on Google App Engine. The GitHub project for the Opark backend is on https://github.com/nibarius/opark-backend