Kanamara Festival (Warning: Adult Material)
If your into penises, the Kanamara Festival might be an interesting festival for you to go to in Kanagawa Prefecture. The festival itself is a fertility festival, with giant penis statues carried around the streets. The story of how it came to be goes a little something like this (taken from http://wikitravel.org/en/Kawasaki)
"Once upon a time, but in a land not very far away if you happen to live in Tokyo, there lived a beautiful innkeeper's daughter. Alas, an evil demon with sharp teeth had taken a liking to her. The demon had courted the girl, but she had stayed pure, and one day the demon learned that the girl was engaged to be married the very next day. So that night, the demon snuck into her house and crawled right up inside her! Our heroine, terrified but helpless, told no-one and the marriage ceremony went ahead as planned... but on the night of the wedding, when her new husband tried to perform his conjugal duties for the first time, the demon's sharp teeth went snickety-snack! and the poor man was turned into a eunuch. And the tale tells us that her next husband met the same fate, although the details of how they conned the village idiot into marrying her have not passed down to us.
It was clear that things could not go on like this, and the whole village met to discuss the, shall we say, prickly issue. After extensive deliberations, a candle lit up over the blacksmith's head: "Why not," he said, "why not deflower the girl with an iron phallus?" The metal tool was duly made and tested, and upon chomping down the demon found that it had bitten off more than it could chew; whimpering, it crawled out and slunk off to hide in a dark corner and nurse its broken teeth. The blacksmith married the girl and they all lived happily ever after... except the demon and the two eunuchs, that is."