Here's something to add to the cron capabilities of Matukio when you get a chance...
It would be great to be able to cron a reminder to users of a booking they have made X number of days before an event is to take place. For example, I am using Matukio to manage internally held courses for our department and I would like an email sent out a day or two before reminding people that they have signed up for the course. Ideally I'd like to send out two emails - one 7 days before the course and one 1 day before the course. For now I'm croning that with my own script but it would be a good addition to Matukio. If you wanted to get fancier you could have a parameter for each event to determine if reminder emails should go out and an override email template for each event.