Michael May

Carl Luepker was 10 years old when he first noticed his right hand twitching slightly when he played piano. It was like it had a mind of his own.

When he was 12, doctors diagnosed him with a degenerative nerve disease called dystonia. The disorder causes nerves in the brain to misfire, causing uncontrolled muscle spasms that get worse over time.

George Foreman at 25 years old was a fearsome champion: 6 foot 4, biceps thick and gnarled as oak, a permanent scowl on his face and a right hand that flattened every opponent he faced.

So when Muhammad Ali challenged him in 1974 for a championship fight dubbed the Rumble in the Jungle in Zaire (now the Democratic Republic of the Congo), most bets were on Foreman.

Ali was seven years older and past his prime. He'd had his title stripped after refusing the Vietnam draft in 1967 and was struggling to become a contender again.

Cameron Robert/NPR

Editor's note: This story contains some explicit language.

The connection between Killer Mike and George Clinton might not seem immediately obvious. One is a 42-year-old Atlanta rapper who, alongside El-P in Run the Jewels, sells out shows across the country without the boost of radio play. The other, now 75, founded the pioneering groups Parliament and Funkadelic in the '60s and presided over a funk empire whose onstage manifestations included dozens of musicians and a spaceship that descended from the rafters.

Editor's note: This story contains some explicit language.