Doctor and Dentist offices sometimes have systems that will call patients and notify them of their upcoming appointment.
These systems are aware of answering machines, busy signals, no answer, etc.
If it hits one of those, i think it usually redials in 5 minutes or whatever.
Once it answers it plays the message to them, and it can ask them to press 1 to confirm the appointment, or 2 to reschdule or whatever.
Is there already something for asterisk that does this, i do not want to write this if I do not need to.