At the dorm with Childish Gambino
Here's a case of rapping for a famous rapper, but long before the fame. In 2004, Donald Glover was just another kid at NYU. In a couple more years, he'd be writing for NBC's 30 Rock, and eventually he'd have a career as Childish Gambino, but in this clip, he's just freestyling with another young rapper at school. The other guy is Chaz Kangas, and he's still making music today.