Yeah I have, mainly when Ive got Uni work to do. Although theres been the odd occasion when I dont sleep all night for various reasons.
Yeah, I once had several days of none to very little sleep at all. I have no idea why. I was really tired after that though.
I became nocturnal for a while a couple of weeks back. Just started getting up ay 7pm and going to bed at 9am for no apparent reason. That was fairly inconvenient. I had to slowly fix it by going to bed an hour later every day until I finally became diurnal again.