The storm 'threw a monkey wrench into' their plans for a picnic. [=the storm ruined their plans for a picnic]
After many years of disappointment, she finally 'got the monkey off her back' by winning the championship.
Our teacher warned us not to try any 'monkey business' while she was out of the room.
(..) Ahh. Where's dear William? Will! Will! Elizabeth! Monkey! I can't move it! Come on! Will! Elizabeth! Why, thank you, Jack. You're welcome. Not you. We named the monkey "Jack." Gents, our hope is restored! Any of you so much as thinks the word "parley," I'll have your guts for garters. Will! (..)2003 Pirates of the Caribbean: The Curse of the Black Pearl