I recently worked with a 4th grade class and we read the book My Dog is as Smelly as Dirty Socks. Afterwards, I had the kids do a self portrait adding similes about themselves in the same way they do in the book. Here are some examples from the book.
And here are some of the student results! (They all wanted more time, but we ran out of it!)
They all seemed to enjoy it and have a lot of fun while practicing some figurative language.