Feature request: a task to be run just once or on event

Suppose PA announces scheduled maintenance. I want to be able to perform a task immediately before this event. Right now I would have to make a daily task and not forget to remove the task the next day. It would be great to have the ability to run the task just once or on event.

You could write a state file when the task starts and them, when it is run, check for the state file and, if it's there, don't do anything. Then you can trigger a re-run just by deleting the state file.