The longest by far was about 50 hours during a trip crossing 12 time zones. In order to try and eliminate jetlag, I stayed up for quite a bit of time before the departure, expecting to fall asleep when I got home (would have been perfect timing). But then, instead of sleeping like I had planned, I stayed up until 2 am.
This might not be weird for some of you guys, but I woke up 12 hours later. So, during that trip I did 3 things: stayed up for longer than I had before, slept continuously for longer than I ever had before, and woke up later than I ever had before.
My sleep cycle was so messed up for a couple days >_<