The Nut Dice Ring is fine for occasional impromptu dice-rolling needs, but it's nowhere near functional for regular play. If you're going to wear jewelry to support your tabletop gaming habits, it might as well be with the Dice Ring.
A spinner ring, it features numbered outer bands that spin in the grooves of a larger inner ring that you wear on your finger. Spin that ring (or rings), wait for it to stop, and the number the arrow points to will be the side of the dice that faces up.
The Dice Ring is made from 316L stainless steel, which should help it avoid scratches, dents and all manners of tabletop gaming abuse. It comes in a variety of styles, from r4 (a four-sided dice) to r20 (20-sided dice) to r100 (double-bands for a large side count) to a few unorthodox ones (spinners that represent playing cards). To ensure fair rolls, the numbers are distributed across the band such that there's no concentration of high or low numbers in succession.
With these dice rings in tow, you can throw down for an impromptu round of D&D (or whatever you guys use dice for these days -- I've been out of the tabletop loop) without having to carry any actual dice in your pocket. That means, no more losing those little things since all the dice you need can be slid over your fingers. And if you're frequently nervous, those spinners should make for a great stress relief tool that's a lot less troublesome than biting your nails or endlessly tapping your foot on the floor.
Currently, the Dice Ring is fully funded on Kickstarter. Project is still open, though, with pledges starting at $15.