This is one of my favorite activities to do in the trigonometry unit. After students learn about the unit circle, including positive and negative angles in radian form and graphing sine & cosine waves, this activity creates the perfect transition to graphing tangent and cotangent functions. The activity is laid-out step-by-step so that students can follow the instructions without a teacher by their side. It is an outstanding small group activity, but I have used it as a homework assignment, as well. It produces excellent discussions within small groups and is an excellent alternative to lecture and would be a fantastic choice for an observation.