It's Marching Band Camp time for many high schools in July and August. When my boys attended band camp, their band director helped boost section spirit and unity by having each band section come up with a funny musical skit or short music selection to play at the end of each day. Everyone voted and the winning band section got a special prize each day.
Another way to create section unity is by wearing matching section t-shirts or caps. Here are some fun musical instrument t-shirts that make great section tees: