Gifts for day camp staff

My son has attended a day camp this summer that has totally exceeded my expectations, largely because of the amazing staff.

He has three weeks left before school starts again, and I want to be able to give the staff a group gift. (I'll buy a separate gift for his primary camp counselor). I'm not really sure how many staff members there are, and I know he doesn't interact with all of them on a regular basis. But I know that they all collectively make the place a positive place to be.

Any ideas on a good group gift. Most of them are either in college or are recent college grads.