"Hearst Magazines and Yahoo may earn commission or revenue on some items through these links." When unexpected guests show up at your doorstep or you need to get creative with your home's sleeping ...

For the occasional guest, there is the sofa bed, Hide-a-Bed, day bed, trundle bed, folding cot and futon. But when floor space is really at a premium, walls and ceilings seem ideal places even for the ...