The monthly calendars only display when you are using
Day/Week/Month view(s) and when you are displaying the
calendar as 1 day, 5 workweek or 7 week.

Follow these steps:

1.  Make sure you are on have selected "Calendar" in the
Outlook Shortcut bar or in the Folder List.

2.  Choose the View Menu and select Current View, then
choose either of the two Day/Week/Month views.

3.  Then click either 1 day, 5 workweek or 7 week icons
on the Standard toolbar.

Hint:  The small calendars will not display in Monthly
view.

Hope that helps.

Cindi