In "The Mad Real World" sketch, most of Dave Chappelle's lines were improvised. Also, the part where Tron, Tyree, and Faze run when they hear a siren was not planned. A siren just happened to go off while filming.
"The Mad Real World" was inspired by David Edwards's experience on the second season of The Real World (1992). Edwards was kicked out of the house by the other cast members. Edwards is a friend of Chappelle's and Chappelle helped Edwards to become a cast member on the series.