The Cat in the Hat Knows a Lot About That! has 40 half-hour episodes. PBS Kids renewed it for a second season of 20 episodes which premiered on September 10, 2012. A 20 episode third season is currently in development. Each episode features The Cat in the Hat (voiced by Martin Short), who leads neighbours Nick and Sally, the Fish, and Thing One and Thing Two on a variety of adventures in his "Thinga-ma-jigger", a Seussian contraption that can sprout wings, pontoons, booster rockets, change size, and do just about anything else necessary to further the adventure. The adventures are prompted by a question posed by either Nick or Sally
The Grinch Grinches the Cat in the Hat on December 2, 2011 until December 9, 2013. The Grinch wakes up in a good mood one morning until his reflection in the mirror prompts him to repeat the "Grinch's Oath" and prove himself a Grinch. Meanwhile, the Cat in the Hat goes on a picnic. Their paths cross when the Grinch can't get his car around the Cat's, and things quickly escalate into a fierce car chase after the Cat unintentionally insults the Grinch by calling him "Mr. Greenface." The Cat returns to the safety of his house, but the Grinch follows him there and tampers with his voice