I have had them, although not as dramatic as Hepola's book. I did the heaviest drinking alone and would wake up not knowing how I had bought things. I would order things on Amazon and the package would come and be a complete surprise. I sent letters to people blacked out. I think most were brown outs though; I would remember pieces when reminded. When I was younger I had a couple where I got wild and did embarrassing things I didn't remember later. I've driven home blacked out a couple times too which is terrifying.
Thankfully I never need to do that again.