These can be pretty hysterical in the right circumstances. Create a
text object. With the text object selected, click on the Animation
Effects button on the tool bar (the one that looks like a yellow star),
and then click on the "flash once" button. Go to slide show and see the
message quickly flash and then disappear.
More PowerPoint Flash tips, Free PowerPoint templates at:
http://www.sameshow.com/other/powerpoint-tips.html
http://www.sameshow.com