I created my first inpage (css/div) popup! If you look at the Salt Lake Calendar, you will notice that the box for June 16, 2012 says that there are 8 items for the day. If you click the words "click here to view" the page will dim the calendar and display the eight items in the center of the page.
Clicking anywhere restores the main page.
The code for an in page pop up is a bear. Regular popups are easier, but the in page variety is slightly better for end user navigation.
Having added my first in page popup, I will probably add more.