I have found a wonderful tool for demonstration...it's called a flex-cam. It is a camera with a long flexible neck (about 10") that hooks up to my TV (mounted in the room). I aim the camera down to my work area so the kids can see my work "live". It's awesome. It has so many uses. You can also hook it up to a vcr and record. A science teacher told me about it.
It comes in very handy when you're trying to demonstrate detailed drawings--for example, when I am teaching how to draw facial features, the kids draw right along with me. It's so much easier than the chalkboard...especially with shading. This way the kids stay right in their seats and work/watch from there. Behavior is very good.
I have also noticed a huge improvement in their work. (I teach 7th and 8th grade)
Cost is about $700.00 I was able to get it thru monies given thru a Teacher Technology Initiative program our school was involved with.