Nothing quite like 16, 2-4 year olds to keep your Sunday mornings interesting. I've only agreed to do this class occasionally so that the other sunday school class (5 years to 15) can better focus without being responsible for their little siblings.
It was only slightly less stressful than preaching. But less preparation time.
On a side note it felt strange knowing most of these kids since birth. Or even having attended several of their births.