In many cases, students in small groups of three or four will simply split the work among members of the group with little actual interaction involved. For a small group activity to work as a teamwork-building exercise, it has to specifically require collaboration and communication among students. For example, a scavenger hunt in which students work together to find objects in the room or in other rooms that are examples of various geometric shapes.
Projects usually require splitting some parts of the work among members in a group. However, projects done in pairs require the two students involved to interact more with each other to determine, for example, what should go into the project and how it should be displayed. Pairs also make one or more students sloughing off while the others handle the work far less likely. While there might be some concern about competing egos, pair activities actually help students learn the necessity of compromise to make a collaborative effort work.
Games in general can encourage student motivation, but those with teams of four to six students can also support teamwork. For example, a quiz game where teams are given a question and allowed a 15-second huddle to come up with the answer together. This encourages students to pool their knowledge to come up with the best answer, and also requires them to form a consensus when different team members have different ideas -- which are both key elements of teamwork.
Subjects across the academic spectrum require writing in some form, and when term papers are due, peer editing in small groups can help students improve their writing and their teamwork at the same time. Teachers should put students in groups of five or six, each with a draft of his term paper. Student should read their papers aloud, after which the other group members will offer some free-form critique. Next, each student will list one strength and one weakness about the paper. This format encourages teams to manage time effectively so everyone gets a turn, and lets them practice offering constructive criticism.