Many people have the experience of using the Calendar,it does facilitate our works and lifes.But most of the Calendars are based on text alert, that means you can only get the reminder event in front of your computer.
So I think if the Calendar can remind me by phone.If I want to achieve this idea, I need a Calendar that can provide me APIs, a technology that can make me to call through programming.
Fortunately,these technologies for this idea have been provided ,Google Calendar and IVR(Interactive Voice Response, based on phone call).
I've posted some articles to introduce IVR.You can view them here:
IVR used in Voicent Gateway
IVR used in Facebook