HGTV's Carter Oosterhouse shows how to build a pony wall, sometimes called a knee wall, which is a short barrier that can help break up a large room into different spaces while still allowing the room to feel open. Start by measuring the area where you want the wall, and then cut your framing boards to fit. Assemble the frame, and then set it in place. Make sure the frame is plumb and square, then attach it to the floor and adjoining wall. Add another beam to the top of the pony wall, and make sure it's level; if it's not, use shims to level it out. Cover the wall using drywall or half-inch medium-density fiberboard (MDF). Paint the wall, then finish it out with trim. For a functional, attractive finish, consider attaching a top plate of 3/4" poplar with crown molding underneath.