I don't think so... there are a lot of idioms or expressions in English that are similar to 熟語 or 成語 in Chinese, but I can't think of a particular one that describes courage or bravery.
The previous answer is a direct and informal saying. However please note that it should be guts, not gut. Technically gut is the whole 腸, but because it is a whole bunch of things piled upon each other in our stomach, people usually call it _guts_, and things that belong to it _gut xx_ (e.g. I have a gut feeling that he does not love me.)
Or, depending on the context, you can say, "He is fighting a battle he can't win against the boss. He must be out of his mind!" "His friends' constant encouragement filled Peter's heart with courage. He became more prepared to brave the frightening side effects of the chemical therapy." "Are you nuts? [nuts = crazy] Why did you throw eggs on Sir Donald?"
2006-11-02 00:46:40 補充:
樓下:應該是 The team is all fired up. To fire up 是令到充滿幹勁的意思,這裡的 fire 是動詞,是已被 fired up。回答:我一時想不到 Have you... 後面可以填什麼字。唯一想到的是:You are so brave. Are you on medication? 通俗來説就是:你咁沙膽,啪咗藥呀?留意,如果你的You are so brave是評論他某一次的行為,一般是You were so brave (除非你指的brave是正在進行中、或你是說他一直都這麼brave,你就會說You are so brave)。