The aim of the game is for each student in the team to draw one part of an animal, person or character, combining their efforts to hopefully produce something resembling the real thing. The students must listen carefully to the part you say at each point, quickly drawing it and passing the drawing on to the next student so they can do the same. You then judge the completed drawings at the end of each round and award points to the teams who did best.
For example, you might tell them to draw a monkey. With each team ready to go, say the first body part, which might be "tail!" the first student then has around 10 seconds to draw a monkey tail somewhere on the paper before passing it on to the next student in the team. "Ears!" might be the next part, the mouth, arms and so on. Mixing up the body parts adds to the fun so feel free to announce them in any order you please.
Change the order after each round so whoever started the first drawing finishes the next or allow them to move around as they please between rounds. A good idea is to allow the last person to draw "anything!" to give them a chance to complete a possibly disjointed picture.
Here are some examples of things I got my Japanese ESL classes to draw:
Animals: monkey, giraffe, cat, dog, panda, koala, tiger
People: yourself, Ichiro, Harry Potter
Characters: Pikachu, Super Mario, Anpanman, Minnie Mouse, Doraemon, Sponge Bob
And here's an example of the order I would get them to draw the parts in:
Monkey: ears, tail, mouth, arms, legs, body, head, nose, anything
Giraffe: neck, legs, body, eyes, nose, ears, head, anything
Harry Potter: broom, glasses, legs, arms, body, clothes, head, anything