I've always thought that Aeolus's bag of wind from The Odyssey would be a great item for a D&D campaign. It's a bag with a wind inside it: point it in the right direction and open it to blow your ship across the sea, or knock your opponents down, or blow out a fire, or whatever. The effect is powerful enough to be useful, but specific enough to force players to think about how to turn it to their advantage, and the fact that it's a one-use item means you don't need to worry about the PCs sudd...
