Have a large glass container sitting by the entrance to the assembly. Fill the container with pom poms and have students guess how many pom poms are inside. Announce the winner at the end of the assembly and give the winner a school T-shirt.
Teach the students a cheer at the assembly. This is an interactive activity that will force the students to be engaged. It will also allow them to know a cheer when they attend sporting events.
Have a tug of war competition between teachers or groups of students from different grades. Students watching from the sidelines can cheer for their friends and favorite teachers.
Have a pie eating contest using football and basketball team coaches, assistant coaches or teachers. You can blindfold them to add to the intensity.
Hold a game of musical chairs, using a group of teachers or athletes. This will be very entertaining for the crowd to watch.
Have a dance competition between a group of teachers and a group of students. The crowd gets to judge the winner at the end of the contest.