Idk if it’s my favorite but I remember the Justice Friends from Dexter’s Lab. https://dexterslab.fandom.com/wiki/Justice_Friends

MILF Island

the scary door from Futurama

“Ow My Balls!” from Idiocracy.

You were both made to laugh and at the same time be the point of the joke for laughing.

McBane from the Simpsons. Someone edited all the small clips together and they make a coherent 80s action movie parody.

The Wall in Solar Opposites.

Does that count? It’s not a TV show in the show, but it is pretty much a second show embedded within the main one.

It’s great how they mix episodic and serialized shit together like that, too. You got the wacky alien one-offs, and then you have a large story unfolding within the tiny world of the shrunken people that live inside Yumulak’s wall.

Some time ago there was a website where you could stream a whole collection of shows-within-other-shows. Like, you could have Itchy and Scratchy listed, just like in a streaming platform. I think it was called NESTflix.

I’d legit watch All My Circuits from Futurama.

And I’d probably shamewatch whatever Mojo put out in the marvel universe.

Psycho Dad, no question.

First that comes to mind is Itchy and Scratchy (The Simpsons)

Wormhole X-treme!

Wormhole extreme from SG-1

Climbing for Dollars from The Running Man.

I prefer “Terence & Philip” as my South Park Show within a show.

I’d argue “Sanctuary Moon” is a more enjoyable show than Murderbot.

And who can forget that show with the “I’d buy that for a dollar!” tagline? Evidently I can, because I can’t remember what it’s called.

Parking Tickets in I’m A Virgo.