dueling tree
Paintballs make excellent targets, and explode colorfully when hit.
Use straws as tees to hold them off the ground.
Another vote for clay pigeons? Fun making the pieces disappear from the backstop. No cleanup is even better.
Anything over 3000fps does amazing things to tomatoes and watch it though a scope at 100yards. Good times. No clean up except maybe couple drops of juice. Lol.
Btw, don't let the wife know your taking her tomatoes, got caught a few times. Lol.
When you can't bring things other than targets, I've printed some of these: Targets - Print your own fun game shooting targets and Free Targets for Shooters!
They have your basic darts games, along with battleship and golf. My kids really find it fun and makes for some competition without the mess.
I need to remember this.
In the past, I'd stop at the dollar store with $20 on the way to the range. I could always find plenty of things to keep me busy for quite a while.