I remember an exam I once took.... it was a two-hour essay
paper.
My bladder was at high tide.... and the examination hall exit was
just next to me.
However, there was so much to write that I didn't even dare to put
down my pen and run for the loo. And really, I wrote and kept
writing until just before the invigilator told us to put our pens
down. 
Pretty funny when I look back and think about it, though.
