This application is intended to help you to account the times you spent for your projects. From the most often used calendar entries simply choose the one that you start working on. ReCal creates a calendar entry and prolongs it automatically while it is active. When you switch to another activity simply select it from the menu and ReCal stops the previous to resume with the new one. Once you are done or when you have a break just stop the running activity. All with a simple menu selection.
If you use a CalDAV (iCloud) calendar the app will automatically synch your mobile device calendars to reflect the current session time.