Fill a large bag with as many small objects as there are students in your classroom. Instruct one student at a time to come to the front of the room and pick an object from the bag. Give the student a minute or so to think, then have him go to the board and write a simile comparing the object to something else. For example, in the student pulled out a baseball, he could write, "The baseball is as white as a piece of chalk."
Write out 20 short sentences using similes and make enough copies for your class. Instruct students to cut out the all the words except for articles, which can be left on their nouns, and rearrange them into as many short simile sentences as they can think of. Students will copy down their sentences on a piece of paper. After, show students the original sentences and ask for volunteers to read any similes they came up with that were different from the originals.
Show students five or six humorous, color pictures on the overhead. Give them two or three minutes to examine each picture and write the funniest simile they can come up using one of the objects in the picture. Tell students beforehand that, in this case, funny does not mean nonsensical -- for example, a simile like, "That giant walks like a fish," may be funny, but since fish do not walk, it doesn't work as a comparison. After all five pictures, have students share their funniest simile and have the class rate their funniness with applause.
Fill up a hat or a small container with slips of paper with various topics written on them. The topics should lean toward fun or silly, like "favorite icecream" or "getting your cheeks pinched by relatives" -- the levity of these topics improve student motivation. Have students pick a topic from the hat and write a 10-line poem on it using at least three similes. Tell students that the poem doesn't have to rhyme, but it should at least have a certain rhythm. After, have volunteers share their poems with the class.
Instruct students to write 10 sentences using similes. Have them switch their papers with other students, and provide them with paper and drawing materials. Instruct students to make a whimsical drawing of two or three of the similes on the list. For example, if one of the sentences was "John ran fast as a train," the student could create an illustration of a person in a train neck-and-neck in a race. Ask for volunteers to share their drawings when everyone is finished.
Hand out a single-page story that has at least five examples of similes. Students will read the story and underline or highlight the similes. After, ask students to rewrite the each of the similes three times using a different comparison, for a total of 15. After, have volunteers share their new similes. Discuss with your class how using a different simile can change to tone of a sentence, such as by adding humor or drama.