I had an enjoyable half hour assembling a piece of furniture from IKEA, before returning for some late night text composition. It goes much faster with a power screwdriver and a good set of bits. (Also, a 16oz hammer makes tapping in dowels directly satisfying.) But if you want to grab hold of ingenuity in a tangible sense, go build some Cubitec.
Dina and I are building a wall’s worth to hold the books in the office; great fun.