There are plenty of TV shows that have their own RPG now, from Altered Carbon to the Buffyverse. But that door swings both ways. See which tv shows began as RPGs.
Roleplaying Games and television have a storied history. RPGs and the movies also have a storied history, but it's less of a tale of cool ideas taking new form, and more a tale of irony, fumbled attempts, and Jeremy Irons squeezing every last ounce of blood from the set he's chewing on.
We've talked before about why a D&D movie is a tricky thing to accomplish, notably that it requires a mix of humor and an understanding about what the rules are, what the game is, and why people love it so much. Otherwise you just end up with a generic fantasy story wrapped up in some D&D trappings, but touching on nothing that really makes it feel like D&D.
Or, as Gygax did in his original concept for the script, you cling too tightly to some idea of whatever you think D&D is supposed to be and you end up with something like the original draft of the never-produced D&D movie:
This is your dungeon," the Nightking explains, "You are in it. There are no guards. The doors are open... which door did you come through? Can you remember? Was this the door?" In his villainy, he continues, "You are surrounded by my Underworld. The choice is yours." They can rem...