Today, it's the Classen Grill in Oklahoma City that is the restaurant of the day at Jane and Michael Stern's Roadfood.com site. I haven't eaten there, but I will after learning that it serves migas.
Classen Grill is within the Classen Circle in OKC, which is an old alignment of Route 66. According to Jim Ross, who wrote the "Oklahoma Route 66" book:
The junction of Classen and Northwest Expressway was known as the "Classen Circle" from the early 1950s until it was reconstructed in the 1980s.
My wife and I ate there about 4 years ago. Good onion burgers.