"Rolling" Calendar

Does anyone have any ideas on this?

I’d like to create a web page that is a “rolling” calendar. My wife wants to be able to display a calendar that shows how many volunteers she needs for morning and afternoon sessions.

She, who knows nothing of HTML, should be able to upload new calendars as often as she needs to but she shouldn’t have to create the calendar file each time.

Is there some 3rd party application out there that will do this? Or is there a way to do it with a database?