I just finished the Cave of Ordeals in The Legend of Zelda: Twilight Princess!
It is a vast cavern spilt into 50 different 'rooms', each filled with enemies. It's not a good idea to enter without a full quiver of arrows, a (few) stuffed bomb bags, and no potions in the bottles you have. It was fun, though. If you have the game, I'd suggest you do it.