My personal top 5 favorites:
5. A cartoon I've unofficially called "Leave the Flowers Alone": a child picks flowers, thinks of picking more when the first ones wilt, but reconsiders when he sees the living flowers shrink away in fear. When the child does the right thing, a burst of rosy hearts appears in the sky as upbeat music plays.
4. "O Imagination/The O Song": a musical cartoon with stream-of-consciousness lyrics, telling a story full of long-O words. Animated by the Hubleys, just like the "E Imagination" cartoon in Episode 1.
3. "A loaf of bread, a container of milk, and a stick of butter." The one thing that puzzled me as a girl: why a generic "container", instead of a size (gallon/quart) or type (carton/bottle)?
2. "Cowboy X": I always had mixed feelings whenever X was the letter of the day; a lot of the segments about that letter seemed negative or even scary to me as a girl. But the Cowboy X cartoon was an exception. The narrative was clever ("it's so crazy it just might work"..."they really weren't very smart"), and the "getting off on a technicality" ending would make any mischievous toddler laugh out loud.
1. "1-20 Raga": I don't know CTW's official title for this one, but it's the Hinduesque counting cartoon that aired (in English and Spanish) during Episode 276. The strange instrumental music, the psychedelic patterns, and the four-armed figure counting on his fingers all fascinated me as a girl.