Just about as simple an instrument as can be....
YOU WILL NEED:
Pipes of various lengths, not sharp or rusty
A styrofoam box
MUSICAL INSTRUMENT BUILDING - THE PROCEDURE!
Lay the pipes across the styrofoam. Test the sounds to be sure that they sound good to you. Discard any that don’t sound right.
If your pipes are rolling around on the styrofoam consider two possible strategies. Pinch off little bits of styrofoam to create small notches for your pipes to lie in. Or, put duct tape strips across the styrofoam with an extra bit pinched up to separate the pipes from hitting each other (see below).