There is an ancient tradition which originated in the Hebrides. During the day of Hallow's Eve, the young maidens of the islands go out and around to collect as many nuts as they can find. That evening the nuts are carefully roasted. A maiden would then offer a roasted nut to a gentleman of her choosing. If he were able to crack the nut with his bare hands, then he would win the heart of the maiden.

Okay, the whole thing is a lie. But it sounded fairly plausible, didn't it?! I am sure the actual answer will be at least as interesting.