Yeah. I was shooting some this morning at our local range. They're quite easy to hang and a lot of fun, done properly. We've got 12X12 steel squares hung at 100, 200, and 300 yards. The square steel is hung beside our target holders so that you can either post a paper target, or shoot the steel, or both.
It's best to use steel rated at AR500 hardness and when hanging the targets, angle them so that ricochets go down into the dirt. It's also helpful to have the target swing or move to absorb some of the momentum of a bullet strike.
Make a 2X4 vertical post. Do it in such a way that it will stand vertically at your range with the top at chest level. Cover the rough end with duck tape.
Get some cardboard boxes of about the size you want the target to be.
Get a big packet of party balloons & inflate them so the just fit into the box.
Put the balloon into the box & set the box on top of the vertical 2X4 in such a way that the box is held up by the inflated balloon.
When you shoot if you burst the balloon the box drops.
If you want to get really fancy put a much smaller box inside the big one & only inflate the balloon to fill the smaller one. This simulates a "vital area" hit.