i have theese kickass spikey knuckles i carry everywhere just to show people not to fuck with me. they're real easy to make. just find a telaphone pole with a wire running down it (usually 1 out of 4 or 5 poles have them) and you'll notice that there are theese giant staple-like things holding the wire against the pole. sometimes, if you pull on the wire hard enough, it'll pop out a couple of the staples which are U shaped so they can curve around your finger with two spikes poking up. then you just get a pencil about the width of your hand and duct tape 2 staples onto it.
-U-U-
I don't think i'd ever actually use them unless i was really really pissed tho.. cuz these things could kill. It put 4 one-inch holes in my wall.