i just discovered a blur feature in powerpoint 2010 that makes it pretty easy to mess with someone in a presentation.
1) start with a title slide and then save the title slide as a JPG
2) next import the JPG into PowerPoint 2010
3) under artistic effects blur the picture
4) then choose to animate with the picture on top of the slide immediately
5) now when someone looks at the first slide it looks ok, but as soon as you present it blurs
let’s see how this works in my next presentation at work!