Over the years we have done hundreds of things, literally
The two that the kids like the most are
1. Breaking stuff....Xmas ornaments seems to be the best, but only work well but only work well indoors because of the easier clean up. ?Outdoors we use different sized clay targets.
2. Long shots! We put a 90 yard buffalo out at one of our tournaments and the kids would rather just soot at that. Seriously, there are a group of kids shooting at it all weekend. We have a big berm behind it, and their arrow arc is so high we rarely loose or break an arrow. This past year we put a can of pop on the side buffalo, that was pretty cool when they hit that.