In June 1985, 17-year-old LL Cool J and his DJ Cut Creator played a gymnasium at Colby College in Waterville, Maine with maybe 120 people in attendance. At this point, his debut album hadn't even come out yet and rapping/scratching was not widely known, so LL and CC give the unenthusiastic audience a little demonstration of what it's all about.
This is amazing. The footage was digitized from VHS by the show's organizer's son and he adds more information about it in the comments:
LL was paid $500 for the show. Since he was the only rap act, he was worried it would a be short performance, so my dad suggested he fill it in with the scratching and beat boxing.
LL was signed to Def Jam. My dad tried to get RUN DMC, but could not afford them, so Def Jam told him he should bring up LL Cool J.