guys, you rock! a great subject Mad-ox, by the way, guys would you mind posting one idiom at a time? not only because it's the rule of the game, but also because it's easier to memorize them, any way here's what I've got:
A white-elepahant: to call a thing a white-elephant, means that it's an unprofitable possession.
it thought that the idiom came when king Siam had a habit of bringing his courtiers to beggary-don't know what does it mean-, he used to present them with a whit elephant, of course the courtier cannot refuse a present given to him by the king nor can he refuse to keep it the result is soon a ruined man.