Some of you guys are CRAZY!
My longest is my fairly usual BLR->FRA->YYZ->YYJ, which is 33 hours in transit, but due to the flight leaving Bangalore at 3 am, there is another 21 hours out of bed time before I even start the trip. And I usually manage to stay awake for another couple of hours once I get home.
So I'm saying 56 hours out of a bed is my longest trip. Tickets ALWAYS booked in Y (woe is me ), sometimes I get lucky on the AC flights.
I have found that with enough sensory deprivation equipment (ear plugs, eye mask, blanket...) I can sleep almost anywhere. And when you are starting at 3:00 am, it is easy...