This is a TPR actitivy which you can apply it to children or beginner students.
You only need two fly swatters. Stick the flies randomly around your classroom, your students must be in two teams. The teacher will mention one of the flies verb, but in present, for example: be. The students in turn will try to smash with the fly swatter the fly with the verb in past participle (been).
The first student smashing the fly win one point for her/his team.