Nature inspired craft - Pine Cone Weaving inexpensive but fun. Pupils can start this activity by finding the pine cones themselves. Different weaving materials will give different results great craft activity as well as a finger strenthening activity.
Little boys will love the idea of working like daddy in the garage and everyone will appreciate the fine motor workout you can get from matching nuts and bolts. This idea (and several more in the same post) from Counting Coconuts.