This is the pipe thing that I made for The Boys for Christmas. This and some ping-pong balls should be a little bit of fun. Without welding anything it can be any configuration.

UPDATE: The Pipe Thing was played with its original mission and then taken apart, running through cars and then became a sort of Dr. Seuss–type instrument complete with a percussion section. So, there is the lesson for today; take something that kids don't normally get to play with and have at it. Well, take most of the sharp bits off first. But not all, 'cuz that's no fun.