Give them a bunch of tools - hammer, saw, screwdriver, ruler, pencil, hand-powered drill, pair of pliers - and some scrap material (left-over planks, some thin

Give them a bunch of tools - hammer, saw, screwdriver, ruler, pencil, hand-powered drill, pair of pliers - and some scrap material (left-over planks, some thin sheet material, some small nails and screws, etc) to work on. Add a bottle of wood glue and some paint, preferably left-overs from other paint jobs to make them feel more at ease at wasting some and appreciate the fact that things don't have to be brand-spanking new to be useful. Help them along a bit but don't get in the way. They might make swords, bows, arrows, cars, horse stables, houses, whatever fits their fancy. The results might not be perfect but they're the work of their own hands and minds. Yes, a 6yo can learn to use a saw, just make sure it is sized accordingly and has small teeth - both because they are easier to use as well as less likely to cause injury.