I've got a B/P mortar that shoot tennis balls at my cabin. Fun when they make it to the neighbors yard (a hunting camp) and bounce around a little. At the end of the firings.
Yep...building cannons, potato guns and shooting various home-made targets and range setups surely keeps things more interesting.
Example, with the heat and drought we had this year, the garden didn't produce well at all. Tomatoes didn't ripen and those that did really weren't worth eating, no taste. But they sure did make for some fun target practice sitting here on the deck with various pistols. Or throwing them in the air, fast drawing and shooting at them with the Judge loaded with .410 #6's.
Punching holes in paper can get very boring. Gotta use our imagination and keep it interesting.
Us grown men can really act like little boys sometimes can't we...but it's sooo much fun.