Are you running out of ideas to reveal information on your flipcharts? Try the translucency feature. Place an object (picture or shape) over the answer you want to reveal. Next, set the action on that object to be "More Translucent." In the "Translucency" box, type "50." While in Presentation Mode, if you click on the object repeatedly it will take approximately 5 clicks for the object to fade away and the answer to be revealed.
I have seen flipcharts with maps displayed using the translucency feature. For example, a snapshot from Google Earth on top of a Google Map of the same area. Or, a historical map on top of a current map to compare the two.