While we're on the subject of the undersea operations, I was researching projects recently for a group of youngsters to have a crack at, and this one really took my fancy. It will take a bit of research to see how I can replicate some of the pieces with UK suppliers, but it looks like a lot of fun.

www.seaperch.org

The wonderful site has detailed instructions and videos, and in depth sourcing information. There's something about water that really appeals to some children, a sense of adventure that might just have a touch more allure than bumping off walls (although I hope plans for bumping off each other's robots will be exciting enough for now...)

It strikes me as an ideal arduino control candidate too for future tinkering. Time to scour the skips for pvc piping and old noodles :-)