I was watching "Beginning Responsibility: Being a Good Sport" and thought that the boy looked familiar but couldn't place him. "Let's Measure: Using Standard Units" just came on Pluto and, lo and behold, it's the same kid:
(https://forum.rifftrax.com/proxy.php?request=http%3A%2F%2Fi267.photobucket.com%2Falbums%2Fii301%2Feegah%2Fkidfromshorts.jpg&hash=721715766b5caa5a091097e0f59b78e998854a88)