Here's the list of answers we came up with.
Apples
Bassoon
Cabins
Dogs
Eggs
Friends
Girls
Hummingbird moths
Instruments
Jokes (about the players thereof)
Kids
Low Brass
Music
Nobody (a nickname given to someone without a name tag on her bunk)
Oboes
Percussionists
Quartets
Reeds
Skits
Toilet Duty (the counselors know the story behind this)
Umbrellas
Vacuum cleaner
Wanda Higgins
Xylophones (of course)
Youth
Zippers (on sleeping bags)