Idioms are the "peculiar character or genius of a language." They are the keys that unlock the doors to a language's vast landscape — a landscape otherwise circumscribed by users' language limitations.
Native users take idioms for granted, using them frequently. To non-native users, idioms are fascinating enigmas not easily translated into their own language if they translate at all. Non-native users are eager to learn idioms because idioms are ubiquitous.
The activity below uses pictures to create a visual representation of idioms, and it employs reflective writing and games, allowing non-native users easy access to understanding, remembering and correctly using idioms.
I designed and developed this multi-part multi-activity exercise to tap students' spatial, kinesthetic, linguistic, interpersonal, intrapersonal, auditory and logical intelligences, and to ask them to becritically reflective and inventive while they learned idioms. It can easily be adapted to tap their musical intelligence.
When I designed and developed this activity, I was using "The Big Picture: Idioms as Metaphors and Idioms for Everyday Use." The eight units in "The Big Picture" are arranged into 15 chapters, each with its own topic: Ideas, Knowledge, Argument, Emotion, Money, Control, People and Life. "Idioms for Everyday Use" is arranged into 20 units with topics ranging from colors, food, parts of the body, animals, people, weather, medicine, and plants to idioms with the word "and," those with the word "as," those with words that "go together," and nine others.
In preparing for each class during which I'd teach idioms, I reviewed the idioms in the chapter, and I scoured Internet clip art for pictures that would represent the idioms. When I was satisfied with what I found, I printed the clip art, took old file folders and cut them to use as backing, cut the clip art to fit, and taped the clip art to the backing. On the back of each picture, I wrote the idiom and the chapter from which it came.
What follows are the instructions for using the idiom picture cards in class and for additional activities. Depending on the length of your class and other material on which you're working, you may find it best to use this activity over the course of a couple or few classes.

This card illustrates the idiom "food for thought."

Instructions

1. As a large group, review the idioms with which you'll be working.
2. Together, discuss the idioms. For each idiom, ask if students have a corresponding idiom in their culture and language, and if they do, discuss them.
3. Put participants in groups of two or three.
4. Ask students to use the chapter or list of idioms for the activity.
5. To each group, distribute one or a few picture cards that correspond to the idioms from the chapter or the list. You can distribute cards with the same pictures and idioms to each pair/group (which requires much more work because you'll need to have enough of the same cards for each pair/group), or you can give each pair/group its own unique cards. Likewise, you can make a few doubles so only a two or three pairs/groups have the same cards; this adds the challenge of seeing if the pairs/groups agree on the answers.
6. Have participants identify the idiom that matches the picture. Remind them that they should not look on the back of the cards. My students were good about not peeking.
7. Have groups share their idioms with the other groups and explain the idioms' meanings. Be sure the groups show the pictures (you can use the doc cam for this). This point in the activity is excellent for catching and discussing mislabeled idioms. For example, one pair or group may identify a picture card as representing the idiom "a knockout," when in fact another group has identified the same idiom on one of its cards. There can be spirited discussion as to which one is the better representation of the idiom based on the idiom's meaning.

These two cards show two different interpretations of "a knockout."
8. Choose textbook exercises for students to complete together or individually; review exercises for accuracy and have students write dialogues using the idioms that they present to the class.
9. Play Hot Seat, a guessing game to augment student understanding. One student sits with her back to the class (this is key because it helps students focus on the clues their classmates are about to give them, and it eliminates the possibility that students can give other than spoken clues). Classmates choose an idiom to use for the game. Each classmate must provide a clue but cannot use any words from the idiom. For example, for "beating around the bush," clues could be, "something similar to a tree," or "not wanting to answer directly." When the student correctly identifies the idiom, she chooses another student to be on the hot seat.
10. Have individuals or groups write a story that uses idioms. You can assign the number of idioms you want each story to have, or you can make a game of it by asking students to see how many idioms they can use correctly in their story. To tap students' musical intelligence, you can have students create a song (a rap lends itself to this activity) using the idioms.
11. Once students have written their stories, have them read the stories to the class and ask classmates to make a list of all the idioms they hear; then, as a class, have the students identify the idioms they've heard and ask them for the idioms' meanings.
12. Once students have gotten the hang of the activity, you can have them create their own idiom picture cards and use those cards for the exercise.