Teaching Smalltalk

This Thursday I start a Smalltalk class for 4th and 5th graders. I would love to use VisualWorks (and probably would for high school) - but Squeak has more stuff that will be cool for the younger set. I'll probably start off with the Wonderland (Alice) stuff - the Energizer bunny should illustrate the object-message paradigm nicely, and be fun as well. This should be fun, and interesting. I've always said Smalltalk was simple enough for children - I can see how it goes with the 9 and 10 year old set.