** Is there anyway to deny [anonymous users] access **
Yes. Change that account's permissions to not allow viewing (or anything else) and make sure none of the other users have view persions enabled for "All users for calendar".
** force a login to view the calendar? **
Go to the Calendar Administration : Calendar Settings and set "Require Login" to Yes.
Dan O.
[This message has been edited by DanO (edited August 19, 2004).]