This was done by a colleague to show how easily Visio could function as an ersatz PowerPoint tool.
The demo was quashed out of fear that Microsoft would see the then-named ShapeWare Corporation as competition.
If you are too lazy to turn the pages yourself, have a look at this!
Visio Slide Show (http://blogs.msdn.com/chhopkin/archive/2009/05/21/visio-slide-show.aspx)