I really like cron for scheduling regular tasks on my Raspberry. Unfortunately some jobs don't occur regular, especially when the task enables or disables something based on my habits.
Therefore I am searching for a cron-alike daemon on Linux that performs certain pre-defined tasks/commands when a certain calendar entry in an iCal file appear. Time and date when a command should be executed are defined by the calendar entry (event start date), the command itself should not be taken from the calendar event (for security reasons).
The iCal file could be a local source or directly loaded from a remote calendar file (e.g. an exported Google calendar). That would allow to schedule tasks on the Raspberry using a common calendar app on a smartphone.