If you're short on storage space, look below the stairs. Some staircases can be easily converted to hold built-in storage units. This allows you to carve out some valuable square footage for stashing kids' playthings, gym equipment, or craft supplies. If you're blessed with an open staircase, you won't even need to renovate. Consider keeping gear off of the ground, by affixing casters to a plywood board, then stacking containers of various sizes and shapes to fit into the silhouette of the space.