If you need a very simple calendar for entering data into. I created a custom Access form that will allow you to do just that. It's nothing like Outlook or anything, it's just a simple form, because my client at the time, didn't want alot of fluff.
There are two versions:
1) General input for anyone in the database. 2) User specific calendars (select a user from a combo box, and then enter stuff for that user).
There is not security on these, but could be added without alot of trouble.
The zip file can be downloaded from the following website: