I've only slept 14 hours a couple of times in my life, I think. One of those times would most likely be influenza induced - although strictly speaking I dont think hallucinations count as "sleep".
And the other time was when I spent four days without sleep writing my magnus opus on Al-Qaeda at University. I'd lived on black coffee, red bull and pro-plus for all of those four days, but by the end I was running out of money, stamina and willpower, so I handed in what I had, then collapsed into bed at...I'm not even sure what time it was, and woke up about 14 hours later, very confused, dehydrated and aching all over. I think it took me another two days to get back to normal.