The christian liturgical year of services on sundays, holidays and other events follow a complicated system of regular dates and dates that get set by a moon calender. To make it more accessible this website calculates all relevant dates and displays them in one circular interface. 
 
(With 2.6 million members, the Evangelical Lutheran Church in Bavaria is the 3rd largest protestant church in Germany. On their website they feature services for both lay people and christian professionals. -» website)
 
 Open Calender