We've also added some controls in there to take it to additional sleep states.

BBC: A laptop

Of the surveyed workers asked to explain their excuse for playing hooky, 30 percent said they simply needed to relax, 22 percent wanted to catch up on sleep, 14 percent wanted to take care of some personal errands, and 9 percent wanted to miss a meeting or finagle some extra time for an overdue project.

CNN: How to call in sick without jeopardizing your job

By some estimates, 70 million Americans have some sort of sleep disorder, and right now many take only the occasional over-the-counter sleep aids.

FORBES: Sleep On Demand

"It was like, 'No one has ever entered this country before, let's go in and take some pictures, '" says study author Michael Grandner, an instructor in psychiatry and member of the Center for Sleep and Circadian Neurobiology at Penn.

CNN: Does your diet influence how well you sleep?