Sports Day -- Calvin
October 10 is the official Sports Day in Japan. Ostensibly, it is a holiday, but if you have a kid in school, you WILL be attending the official school event.
The student body is divided into two teams -- red and white, indicated by colored caps -- and they compete in a variety of athletic games. These events are interspersed with various gymnastic and dance routines.
The two boy the the picture at bottom-right are cheerleaders for the two teams.