Setting random local notifications on iphone

I am trying to find a way to schedule random local notifications on iphone. I would like to be able to send a random message to the user (selected from a list of messages) at a random time during the day, every day.

I can probably count a bunch of random times and messages and just schedule it for the next, say 30 days or more, but that seems like a mess and doesn't provide a good way for the user to cancel the warnings.

My research shows that cron jobs are not supported on the iphone, so it seems like I can't just schedule a background process to randomize notifications, right?
I also saw push notifications as another possibility.

However, I wanted to ask my own question to see if you have any experts any other ideas.

thank!