Mickey Moose said:
"Racing Cars Counting" (I don't know what else to call it)
That's on my top two as well. That and the Falling Baker Films, starring Jim and Brian Henson. "Racing Cars Counting" is an okay name to give those cartoons. A lot of folks like to call them "Jazzy Spies", but there's really no one name to give them.
Here are other favorites of mine:
-"5 People in My Family"
-"As I Was Going to St. Ives (The "7" song)"
-Holy, Moley, "Eight Balls of Fur"
-"11" with those psychadelic squares (Does that count as a song?)
-1-20 with the Animated 4-Armed Yogi - in both English and Spanish
-16 Samba ("I Love You, Sweet 16")
-The Octopus Blues / The 1-2-3-4-5-6-7-8 Blues