Idioms are more common than you might think. We use them, fairly, regularly.
"Idiomatic" is a board game for, intermediate to upper-int and advanced classes that allows your students to practice using idioms. It includes 24 of the most common and can be played in 2 ways. Students, in both versions, roll the dice and move their counter but when they land on an idiom you can choose what they do. Either they define the idiom and say what it means OR they use it in a sentence. For higher level groups you could ask them to do both, to really test them. "Idiomatic" is best played in smaller groups, you might have to split your class up.