Created mainly for novelty value, this die, surprisingly enough, has 30 sides. Not a platonic solid, it is technically not 100% random, but the sides seem to my non-mathematical eyes to be arranged to minimise this effect.The sides are Rhombuses, arranged in groups of three. It actually makes a useful counter, as it goes up to thirty, and each number is generally near to the next.

To my knowledge, there is only one game system that uses the d30 system - an obscure F1 racing boardgame whose name escapes me at present. The d30 is mainly kept for geek points, or occasionally for keeping track of life in M:TG when paperclips are unavailable.