I do this one most semesters and it goes like this:
Type up a bunch of passages from published short stories that demonstrate techniques you would like your students to imitate. I like to do enough passages that each student will draw something different, but you don’t have to. Once the typing part is done, I print and cut them up, so each student will draw their own little “card.” So crafty, I know.
You can make the exercise technical in orientation—i.e. examples of flashbacks, flashforwards, indirect discourse, etc. I ask the students to read their card and then “imitate” the technique presented, using their most recent workshop story. So if a student has just workshopped a story (or will soon workshop a story, depending on where we are in the semester) about a woman named Lucy who illegally sells exotic parrots and draws a “flashback” card, she will be tasked with writing a flashback for Lucy. This can be a good way to introduce more novice students to the various narrative techniques available to them.
If you want to make the exercise more extensive, you can have students work with the first card they draw, then trade cards with the person sitting next to them and do another imitation (so maybe this time Lucy gets a flashforward) and so on.
Sometimes I make the exercise descriptive, so all the “imitations” are different examples of descriptive language, authors describing apartments and wilderness and oceans and deserts and trailer parks. Good for getting students to be more attentive to the physical world.
You can also go character-oriented. Maybe the Lucy student draws a passage from “Vampires in the Lemon Grove,” where Clyde sucks on a lemon in lieu of sucking on a human, and has to write a scene in which Lucy gives herself an odd substitute for a destructive habit she’s trying to give up. Or maybe she draws the scene from “Last Night,” where the wife that the narrator thinks he’s killed comes down the stairs in the morning, woefully alive, and now this students needs to think about who Lucy would want to kill and why and how she would fail to kill this person and what it means for her that they’re still alive.
Sometimes I make the exercise weird. Maybe the Lucy student draws the scene from “Superfrog Saves Tokyo” where Frog explodes with maggots and boils and disintegrates, and now she has to write a scene in which Lucy physically crumbles in the most revolting way imaginable because why not.