This research focuses on the inappropriate, largely aggressive, behaviors of 344 K‐2 children assigned to a playground prior to the beginning of the school day. Initially, a system for observing large numbers of children freely roaming over a large, open area was developed. This observational method was then used to determine the effectiveness of providing organized games for reducing potentially dangerous playground behaviors. Using a reversal (ABAB) design, it was found that the games, rope jumping, and foot racing, along with an infrequently used time‐out procedure, significantly reduced the frequency of inappropriate incidents. It is suggested that when dealing with large groups, antecedent environmental manipulations may be more practical than providing consequences for the behaviors exhibited by identified individu