While living rooms tend to be used for entertaining company on formal occasions, dens, like other family rooms, tend toward the more informal. In houses that do not have dedicated family rooms or recreation rooms, a den may fill that niche. Dens can also be private areas primarily used by adult members of the household, possibly restricting access to the room by their children. Dens with home theater systems and large screen televisions may be referred to as media rooms instead. Most den floors are made out of wood, carpet or floor tiling.