Many trainers like to include some sort of activity where participants need to function as a team to accomplish the goal. Here's one around building a tower in teams.
In class activity
Ideal Group Size
Uses small groups so limited only by space to assemble sub-groups.
Time For Exercise
Detailed Instructions If Needed
Preparation: Assemble scrap paper and various other lightweight materials and divide into equal portions, one for each team. Give each team a quantity of string.
Explanation. Each team has the task of constructing a tower from this pile of paper, string and supplies. You can only use these supplies, and you cannot attach the tower to a ceiling, wall or other object. Towers will be evaluated in three ways: height, stability and elegance. Each team can choose which of these criteria you want to excel in. Also, try to find ways to involve each team member in this activity. For instance, some team members may fold paper while others experiment with ways to stack them. One member may be a timekeeper, letting you know when 5 minutes remain, 2 minutes remain, etc. Another member might be a spy to check out what the other teams are doing and report back to you. You have 15 minutes. Begin.
Activity. Allow 15 minutes for the teams to construct their towers. Go around with a measuring stick and record the height of each tower. Blow on each tower to rate its stability. Invent some criteria to rate their beauty.
Discussion: Invite a representative of each team to report on how the team worked together: how successful they were in getting each team member involved, how well they utilized the skills of the various team members. Invite comments on whether the result of the group effort surpassed what any of the individuals could have done alone.
When debriefing, it's good to check with the sub-groups as to whether their group spokesperson accurately reflected their own perceptions of how the task went, since often, perceptions will differ WITHIN a team. That's a fruitful path for discussion, too.
Source: Creative Commons Licence from here.