At work we do almost all of our UI design mockups in Visio but because they're static it's sometimes hard to get a feel for what will really happen when people click on things and how usable it is.  In other words it's easy enough to see if the "look" is right, but what about the "feel"?

Well it turns out that you can emulate some limited interactivity using PowerPoint.  I hadn't thought of doing that before until I ran across this blog entry from one of the guys responsible for the Office user interface.  It's pretty interesting and it might well be time to try it out :-)