Plinking!
We still have two old BB guns we'll shoot at cans hanging from trees when we're at one friends house. It's fun because they are so inaccurate and you can watch them.
Funny you mention the casings. We were plinking with a .22 shooting .22 casings three or so weeks ago. An old vet that does his own reloads gave him boxes of them. I don't know anything about it other than his wife saying it was dangerous.