For our students, to review vocabulary about parts of the body.

It's very very entertaining, I have tried it in my lessons and my students  have laughed  and enjoyed a lot. You can ask the students to create their own face or their partner's face or even the teacher's face. Useful to make descriptions, one student makes  a face and then describes it to the rest of the class, the others have to draw it following the description.

 http://www.channel4.com/entertainment/t4/microsites/M/makingfaces/index.html