Back in the day, real early 80's, Busy Bee was one of the top rappers in the NY. His style of rapping at that time would qualify him more as a hype man than an actual MC these days -- strictly a party rapper, calling out Zodiac signs and hyping up the crowd (you can read more about Busy Bee
here).
Anyway, he ended up getting into an 8 Mile situation with Kool Moe Dee, in what most people say is the first hip hop battle. Busy Bee was at a freestyle competition in NY around Christmas '82 (I think...I could be off on the year), and Moe Dee was in the crowd. Busy Bee had a few lines saying that noone could touch him as an m.c. Someone in the crowd shouted out Moe Dee's name, and Busy Bee freestyled a line dissing KMD. So Moe Dee signed up for the competition, and the two of them went at it. The judges called it a tie and set up a second battle for a week later.
Moe Dee and his crew apparently got lost on the way to the competition, and Busy Bee was up on stage putting on a show. Moe Dee pulled up to the club right before the 2 AM deadline, and the competition started. Busy Bee started off with his usual party raps, and then Moe Dee just went off on him. Busy Bee ended up leaving the club before KMD even finished his rap. A lot of people say that this is was a turning point for rap, when lyrics went from strictly party/hype stuff to something a little harder.
You can also hear another member of KMD's crew, Sunshine, rapping during part of the battle.
Here is the freestyle from the second battle:
Busy Bee Vs Kool Moe Dee (mp3)