This is an assignment that can be given after ready the short story "Nosotros, no". Students create their own invention and must present it to the class. The grammar emphasized is commands with object pronouns and the subjunctive. Students should also ask each other higher-level thinking questions after presenting their invention.
I explained the assignment in class then gave two nights for the students to work on it at home before presenting.
I did this in my AP Spanish class but could be modified to other levels.