Patterns and pattern matching is probably a nice direction to go. I remember having a lot of fun playing with Penrose Tiles at the Maryland Science Center in Baltimore. These are really flexible as exhibits. They are fun to just play with, but are also incredibly interesting (I spent about half an hour designing my ideal bathroom floor...) Patterns also occur so often in nature that you can pull in people who are not really interested in math - point out that seed growth in sunflowers follows a well-defined mathematical sequence, for ex. Patterns are also a part of fractals, which are always really cool. The other classic component for math exhibits has been topology - but I get the sense that this has been done to death... I would go for something to do with music - why a grand piano is the shape it is, etc. I would strongly suggest getting in touch with the people at the Maryland Science Center. Though they use exhibit ideas that are derived from previous ones, they put nice spins on them. Also, you might check out the booklet that the Exploratorium produced for their "Mathemagica" (?) exhibit. I think that's what it was called - done in conjunction with IBM sometime in the mid 70's. Kirsten Vanstone ([log in to unmask]) -- -- Kirsten Vanstone Science Educator Ontario Science Centre