As it turns out, Noah wasn't too interested in playing in the leaves. After it was clear that he was not going to move beyond a few tentative kicks around the edges of the leaf pile, I figured he just needed some encouragement and picked him up and plopped him down in the middle of the pile. He was not too thrilled. He spent a good amount of time trying to figure out how to get up without actually having to touch the wet leaves. Sometimes, he really is his father's son.
He did eventually make it out of the pile. And the first thing he did when we got home was drag a stool over to the sink to wash his hands.
He is probably hoping for more cold, gloomy days...