A Portmanteau of the words "sleep" and "vacation".
Sleepation is a period of time completely dedicated to recovering sleep with short periods of wakefulness for eating,drinking(water),vitamin supplementation,hygiene,toilet trips and small periods of non intensive exercise.
Sleepation is a word commonly used by insomniacs and the occasionally sleep deprived.
(On the phone)
John:Let's go to the beach this afternoon,it's going to be a nice day!
It's when you feel like you've got too much work to go to bed, but you are too tired to getanything done. So you just surf the net and procrastinate until you can't stay awake anymore.
Tom: Well I managed to get half of it done yesterday, but then I got stuck in sleepytime limbo and just stayed awake the whole night browsing through facebook...