Thats great!
I have run a bunch of workshop classes from elementary right through to senior high level and the reaction has been very good:
http://al.chemy.org/workshops/I would be interested in hearing what type of activities you do?
In the past I have used several seemingly unrelated random words like
Monkey, Zombie, Dog, Hairy, Ugly, Alien etc... and asked the students to draw something off the top of their head.
Also, worth a try is something like this:
http://weirdblog.wordpress.com/2007/03/ ... agination/Where you have a starting point (line or shape) and the task is to expand it into something/anything.
So there is not necessarily a 'correct' answer, and a lot of it is about the creative visualisation rather than the accurate representation of shapes/form/shading etc... This makes it fun for students who may not see themselves as 'artistic'. If its fun, you break down a lot of those mental barriers in the process too.
Definitely interested to see what you get up to.