We had had some nice storms early in the morning and I thought they had passed but about 30 minutes into my demo a storm started brewing over the horizon. Work became frantic. But another 15 minutes and it took this wonderful right hand turn and coasted off to ruin somebody else's demo somewhere else. After the adrenaline had subsided I actually had a pretty decent painting with a hint of storm clouds in the distance. And the students got to see plein air painting off the cuff and in a flurry. One of my students had a watch and was shouting the time in intervals to ad to the heightened since of chaos. It made for some very intuitive painting for a few minutes. Once the storms curved off we slowed down and analyzed the painting and what had just happened and it made for a very good lesson.