Bob Durnell posted this custom woodworking project over at LumberJocks. The small, seldom used basement of a California home lent itself to be accessed by a trap door. Bob lined up oak boards with the existing hardwood floor. He then epoxied those to an MDF board and reinforced it with iron channel for strength and to avoid warpage.
A well-made trap door like this will last as long as many houses, keeps your attic or basement easily accessible, and can easily be hidden if necessary.