Over the years I have made a hobby of tying decorative and useful knots.
My all time favorite is the Monkey Fist. First used as a weighted end for heaving lines, can be used as a weapon on a short lead and at one time was used in mountain climbing.
My next favorite due to my heritage is the Celtic knot.
Anyone else into this esoteric hobby? I've tried to teach my kids.....but they seem to have no interest.