I promised a set of Johnny Cash duets, and here goes. There's a lot of available stuff out there because Cash had his own TV show about 1970 or so.

"Blue Yodel No. 9," with Louis Armstrong, doing a Jimmie Rodgers song. Don't miss this one.

"City of New Orleans," with the Highwaymen. Willie Nelson handles up on lead vocals.

"I Guess Things Just Happen That Way," with Jose Feliciano, who then does "Earl's Breakdown."

"It's Too Late / Matchbox," with Derek and the Dominoes and Carl Perkins. Clapton and the band do the first song, and Cash and Perkins come out for the second. Awesome.

"Take Me Home Country Roads," with John Denver. Yep, you read that right.

"Wildwood Flower," Maybelle Carter with the Carter sisters. Cash does the introduction.

"Orange Blossom Special / Jackson," with Miss Piggy and the Muppets. Cash has fun with this one.

"It Ain't Me, Babe," with June Carter.

"Doin' My Time," with Marty Stuart.

"Girl from the North Country," with Bob Dylan.

"Ring of Fire," Ray Charles. Cash does the intro.

"Folsom Prison Blues," with the Highwaymen.

"King of the Road," with Roger Miller. Starts with about two minutes of clowning around.

"Darling Companion," with June Carter.

"Will the Circle Be Unbroken," with the Nitty Gritty Dirt Band and a cast of thousands.

"Only Mama That'll Walk the Line / The Shells in the Ocean," with a very young Linda Ronstadt. Cash joins in on the second song.

"Ghost Riders in the Sky," with the Muppets.

"Gentle on My Mind / Little Green Apples / Please Release Me / Born to Lose," with Cass Elliot.

"I've Been Everywhere / By the Time I Get to Phoenix / Galveston / Folsom Prison Blues / Abilene," with Glen Campbell.

"Kaw-Liga," with Hank Williams Jr.

That's twenty, and there are dozens more. I'll come back to this theme.