Traditional: 雞飛狗跳
Source: http://how-to-learn-any-language.com/forum/forum_posts.asp?TID=20848&PN=46
One that made me laugh out loud was 鸡飞狗跳 ji1 fei1 gou3 tiao4, used to describe a situation that is chaotic or out of control.
I love the graphical images that it conjures up in my imagination when I think of the literal meaning "chickens fly, dogs jump".
The political situation has been chickens flying and dogs jumping all over the place lately, sort of thing. I can picture the mayhem of a few hundred chickens and several dozen dogs running amok and chasing each other around all over the delegates and fixtures during a session in parliament :o).
Source: http://how-to-learn-any-language.com/forum/forum_posts.asp?TID=20848&PN=46