Sleeping.

I went to bed just after nine last night, I would say I was asleep by twenty-five past. I woke up about ten minutes ago say quarter to ten. This means I was out for over twelve hours, no need to get up for the loo, nothing, just out cold.
Now I've had a heavy weekend so clearly I needed it. The only time I ever slept longer than this was in my early twenties, when I pretty much slept twenty hours straight through after working three night shifts in a row in my shitty job, WHILE attempting to make it to some classes in college during the day. On the friday of that week I went to one double class in the morning, came home, went to bed around midday and woke up the following morning around eight.
Those are extreme circumstances, but still I am impressed with the body's ability to put manners on us from time to time.
So-while I ply myself with coffee- I have a question.
What's the longest you have ever slept in one singular go?