Nighttime in the desert.  Most people were in their tents and in their sleeping bags by about 7:30 at night, which sounds really early, but which made sense given that a) we would get up around 5:30 in the morning, and b) you'd get up to go to the bathroom about seven times during the night, meaning that you didn't sleep as much as you might think. 

Eventually I got tired of getting up in the middle of the night, and started relieving myself in my tent, just, you know, spraying my waste products all over everything, covering the walls and the sleeping bag and everything else with urine and excrement, coating the tent and all my possessions with micturition and fetid human excreta, smearing my own colonic and bladder discharge willy-nilly over every square inch of my portable home.  It turned out later that that wasn't such a good idea.