Let students know the written report due date and make up a schedule for group presentations and post it. One game presentation per class period may be better than attempting to do two if you have the time and the space. The students enjoy learning from their peers and really engage in the process when given the time. Students may borrow or make their own equipment. Stress that there is no need to purchase expensive materials to complete this assignment.
Creativity is valued over authenticity.
It is probably advisable to assign games to specific groups or present a pre-selected choice of games. Sixth graders an spend an entire class period selecting their games.