For your finger, that is: the "Nut Dice Ring" comes (unthreaded) in standard sizes 6 through 10.
This ring is a perfect piece of jewelry for people who say that they don't wear jewelry. It really does help with decisions (odds I stay home, evens I go out). As proper dice should, each pair of opposing sides adds up to seven.
The sterling silver rings are 88 bones apiece, so you don't need to be loaded to get your hands on one (or rather, to get one on your hand), but jewelry seems like small stakes: I could see the iconic 1-6 pips stamped on all sorts of hex nuts. Then again, I'm not sure I'd put money on the idea... what are the odds that someone's already come up with it?
Hat tip to GearHungry