I can't get my dog to watch much of anything. We leave the TV on for her in the playroom in the evenings, but she usually sleeps through most shows.
Stanley Cup, basketball, old movies, SpongeBob, you name it. But she does get annoyed at me sometimes if I'm cheering because it's a good game or a particularly interesting cartoon.

Our cats watch TV.

Nub loves soccer, hockey, MotoGP, and F1. She likes the movements of the people/things.

Flick is mesmerized when horses appear on TV. No idea why--she's a city cat.

They all like watching the Westminster Dog Show and youtube videos of birds and chipmunks. The random fluttering of wings and chirping gets them all worked up.

Once?

I saw the cat chase Super Mario off the right hand side of the screen, and around behind the TV. His agonal screams were petrifying.

One of the cats was lounging on top of the console TV (pre flat screen). She got up, stretched, looked over the edge and seeing Clinton, took a swat at the screen.

Never had an episode like that. Lol
Our dog does watch TV with is but never reacts.