A blog I read called yclipse had a neat tech tip for using Adobe Acrobat to create basic, low-cost animations in PDF. An example shows an animated diagram of an auto accident.
From yclipse:
Use a multipage PDF for animations
This PDF file is an example of the creative use of Acrobat to create animations. We started with a diagram of an intersection, then created a couple of simple custom stamps. The result is a very useable low-cost animation of an auto accident. Just use the arrow keys or the “next page” button to move from the first to the last.
As a bonus, this file can readily be adapted for use in other situations with similar intersections, because the stamps are readily moveable on the page. (The file can be viewed and used under Acrobat Reader 6, but the full product is needed to move the stamps and to create new ones as described below.)
Read the full post for more details.