A simple calendar with optional CalDAV synchronization. You can easily create recurring events and setup reminders it can also display week numbers.

Contains a monthly view and an event list widget where you can customize the color of the text as well as the alpha and the color of the background.

Contains no ads or unnecessary permissions. It is fully opensource provides customizable colors.

The Storage permission is needed only for exporting or importing events from .ics files.

The Contacts permission is used only at importing contact birthdays and anniversaries.

This app is just one piece of a bigger series of apps. You can find the rest of them at http://www.simplemobiletools.com