A Useful Program/Widget

I am looking for a widget/reminder or any program that uses E-Mails to automatically send a recipient to ask if they will attend an event, allow them to respond, and forward this reply to another user by E-Mail. I understand that Google calendar or Outlook can set up events, but my problem is that these programs will send out invites the minute the task/event is created. I am looking for an invite sent out the day before the event, but I can preset this task/event two weeks in advance.

I am also willing to look into programming such a widget if someone can give a noob in programming like me any pointers.

Many thanks~