Calendars, Multiple Users, Reminders

I have an interesting project that I am seeking assistance with.

I am looking for a plugin, that would allow each user to have their own Outlook-type calendar to enter/manage special events they don’t want to forget. Hopefully any limit on events per day would be around 5 or so.

Then, the system should send notice to an admin who will send out emails to those asking for one on that certain day, etc. Apparently, the emails being sent out are to have that “human” touch. We’ll see how long that lasts. ??

I did some searching, but thought I would attempt to state what I am needing help with and hope that someone understands. ??

I am helping out a friend, so we are hoping there is no major cost to get this done. Thanks for your assistance! ??