“C’est les vacances” means “it’s vacation”. And just like in English, it means that it’s time to do nothing!  

“Il fait un froid de canard” means “It’s freezing”. Although it literally means “It’s a duck-like cold”!

“Tu craches dans la soupe” means “You are being ungrateful”. Although it literally means “You are spitting in the soup”!

“Voler de ses propres ailes” means “To stand on one’s own two feet”. Although it literally means “To fly with one’s own wings”!

“ça ne tient pas debout”, means “It doesn’t make any sense”. Although it literally means “It doesn’t stand upright”!

“Coup de foudre” (the “p” is silent!), means “Love at first sight”. Although it literally means “a flash of lightening”

“Ça marche!” means “that works”(like “my car works” or “this plan works for me”). Although it litteraly means “it walks!”