Kickball
All you need is a ball to play an old-fashioned game of kickball. The rules are somewhat akin to baseball. Create three bases and a home base using whatever is handy. Each team takes turns kicking the ball and running to the bases. Whoever catches the ball can tag the runner "out." Three outs and the teams must switch; one point is gained for every runner who gets to the home plate safely.
Three Musketeers Race
Use markers to create two lines about 20 feet away from each other. The boys should make teams of three and stand with their back together and arms linked, forming a triangle shape. An adult or chaperone yells out "All for one and one for all!" to begin the game. The teams of boys must run to the second line and make it to the first line without becoming unlinked. If the team becomes unlinked, they must go back to the starting line. Whichever teams makes it to the second line and back first without becoming unlinked will win.
Pick Pocket Tag
Give each boy a strip of cloth or bandana to put in his pocket. The object of the game is for each boy to "pick" the pockets of the other kids. Whoever ends the game with the most cloth strips is the winner and the best pickpocket.