There used to be a couple of joints here that had food very similar to In 'N Out, one was here in Parker. Burgers 'N Sports? Something like that. Pretty dang good, I liked 'em. Seems the rumor was they were somehow related to In 'N Out, owned by a former employee or something. Been gone several years, health dept. violations or some such BS, probably threats of lawsuits too.
Then there's that place in The Springs that's also similar, but not quite, Drifters. Also good, but different enough to stay under the lawyers radar I reckon.
Anyway, good stuff. Never had a real In 'N Out burger, I avoid California. But I'm anxious to give it a whirl.
My all-time faves are private, local joints in my hometown in Enid, OK - Lottaburger, Lenox Drive In, and the Flamingo Lounge. Ain't gonna find those burgers anywhere else. There's some killers in El Reno too at Sid's Diner.