Longest period you have gone without sleep?

I have stayed awake in a near zombie like state throughout various long haul flights and in 2011 when I went to Thailand I decided I would stay awake the night before so I'd be sure to sleep on the plane.

Basically I awoke on Monday morning around 8am and done my routine for the day, packing and preparing etc. I then stayed up all night nodding off for no more than half an hour. Had a shower on Tuesday morning to wake me up a bit and then went to Cork airport and flew to London around 12 noonish, my flight to Abu Dhabi was not until 11pm so I went into London for the day and called to visit my relations for a few hours as I had left my bags at the left luggage place in Heathrow. By now I was very tired as you can imagine and once I got on the plane I fell asleep for about an hour and woke from some stupid kids kicking my seatback and then stayed awake for the next 6 hours watching some movies before I landed in Abu Dhabi, I then had to transfer and that took 2 hours and I was then awake for the flight to Bangkok and slept briefly during the taxi to my hotel.

So from 8am Monday morning to the middle of the night early wednesday morning I was awake with only a small bit of sleep caught. However my plan achieved its aim and I slept like a baby and awoke normally in Bangkok without much jetlag! I was almost 40hrs awake! Never again though it was horrid.