Slightly obscure, but cool things to do with your kids (pinched from The Guardian this weekend) ... build a xylophone

Flicking through the paper this weekend, I came across this under the heading 'If I had the time...'. Slightly obscure but kind of cool too:

Build a xylophone by Melissa Viguier

"We began with a child's size mini xylophone. In order to extend this to make a giant xylophone, measuring 1.5m we just scaled up the design. Beginning with the frame, which is roughly A-shaped, we screwed together four pieces of wood - it can be any length; it just needs to be strong and A-shaped. Then, for the bars, we made 25 all from pine, by just sawing the wood into lengths with our hacksaws. Each bar is 2 cm longer than the previous one. Then each bar was drilled at each end (by an adult) using a 6mm drill bit, and all the bars were laid on to the frame, with a gap between the bars of approximately 5mm.

Finally, the bars are held in place by nails through the holes. It's important that they can move a little to resonate the sound so don't nail too close. make sure that the bars aren't touching each other. Knots in the wood, and bends and splits, all affect the sound - but are fun to experiment with.