Just blasting a lot of ammo at stuff that blows up might be fun also but it isn't as challenging and proves nothing about your shooting skills.
You can make it as challenging as you want to.
Put gallon milk jug full of water at 400 yards and attempt to shoot it from field positions, under time pressure. That will tell you quite a bit about your practical shooting skills........
Try "the rifle bounce": 15 milk jug targets, 5 each at 100, 200, 300,. The 100 yard firing pt. has a 4 foot tall screen in front of it. The 200 a 2 foot screen ...... screens may not be touched. (For extra difficulty, separate the firing points by 100 or more yards!) Best time wins.