Hmmm... sounds like that leaves out anything with flour. How about making chocolate truffles?
You could always bring a hot plate or microwave to plug in somewhere.
Since you can't actually "cook" anything, how about showing them how to chop cabbage and make different kinds of coleslaw?
Maybe you could demo different cooking instruments that aren't in the normal kitchen. Some people have never even seen a mandolin or microplane in action.
Luisa's idea for a pasta maker is a cool idea. You could demo making sheets of pasta then let the students cut it out in different shapes. They could take it home to cook.
Maybe do a demo on different herbs. Bring little clay pots filled with soil, hand out seeds, and instructions for growing. Hand out recipes for each appropriate seed.
Will there be a class fee involved to cover purchases such as this?