To occupy my nephew for a few hours I asked him to solve a Rubik's cube that had been on the mantelpiece unsolved since 1992, my own childhood. He solved it in a minute, he's still bored, and I am now also resentful.
@fesshole Get him a 4x4x4, then. If he's spent the many hours necessary to learn to do the 3x3x3 in under a minute, he'll no doubt enjoy the challenge.