If you ever have giving a demostration and had a member of the class/audience ask if you could increase the font size so they could see what you were doing, then "ZoomIT" is a great little application you might be interested in.  It is a non-registered application (not installed into the registry) that you click an icon to start, then use a user-assigned F-Key to turn on during a presentation. Once its turned on, you just scroll the mouse-wheel to zoom into a spot on the screen.  While it does not do screen resampling, so the more you magnify the larger the pixels appear, it is a tiny application (76KB) that sometimes is just right for the occasion.  BTW, it also does screen annotation so you can make notes and do highlighting on the fly.  Give it a try and tell me what you think!