Many wooden items around the home can become a headboard. By turning the old door sitting in the garage on its side and installing it on the wall sideways, a queen or king size bed receives a headboard. Or, a set of wooden closet doors becomes a headboard if you place them upright against the wall. Another option includes attaching the top of an "L" shape wooden desk, no longer used, or a wooden table top to the wall.
An existing wooden headboard can be transformed into a new one with a couple of modifications. For example, by cutting the hump from a rounded headboard you can get a headboard with a straight line across, or if you prefer a curve in a straight headboard, then draw and cut the curve. You can also cut an oblong circle in the center of the wood headboard and place a mirror panel, stained glass design or leave it open.
A piece of plywood can turn into a headboard. As plywood does not have the inherent beauty as a piece of wood, rather than stain the plywood, it would be preferable to paint it to match your room décor. Embellish the plywood headboard by adding wood trim pieces around the perimeter as a border or stenciling a design. Some designs include a flower inside an oval for a romantic room or a cowboy hat with boots for a kid's room.
If you prefer to try an unusual design, look to nature for inspiration. For example, a piece of driftwood can become a headboard in a coastal retreat while a large log--or several when tied together--can become the headboard for a mountain cabin. Or, place round slices of logs in a row and glue to a piece of luan for a headboard. An English cottage bedroom may go with a white picket fence as a headboard or a white-washed gate.