Great for developing motor skills, but also just great fun. No need for expensive equipment or even to confine it to the garden.
Fill a shallow seed tray with sand and a spoon or hands can be used to dig. Encourage your child to name any of the small objects he might bury like a toy car or a leaf or flower.
At the sink pouring water from one cup to another will keep them amused – add foam to hide objects beneath. In time they can help you with the washing up!