I've slept for 16 hours, usually I'd sleep 6-7 a night, but after travelling from san fran to adelaide (having to go san fran to LA, LA to sydney, sydney to adelaide including changeovers) I was utterly shattered as the old qantas plane was really impossible to sleep on, and simply collapsed and woke some time another day.
Not sure on being awake, i recall around age 14 getting German Measles and the skin itch was so intense I didn't sleep at all 2 nights in a row, this was 20 years ago, and late night TV barely existed, there was only ITV that late at night, and damn it was a boring existance staring at walls.