Back before the days of the internetz, if you wanted to know the lyrics of a song, you needed to buy the album, which usually contained the lyrics in the cd cover (or tape cover, vinyl, 8-track, whatever). If they weren't there.. you were out of luck. Now-a-days, you can just Google it or use sites like understandrap or rapgenius, which even offer explanations to rap lyrics in terms that even yo momma could understand (and people who weren't lucky enough to grow up in the 'hood)
Although rapgenius seems to be more comprehensive (and has cool features like the rap map of famous rap song locations and interesting info from whosampled.com ), the site seems to take its mission a little too seriously:
Our aim is not to translate rap into “nerdspeak”, but rather to critique rap as poetry
--from Rap Genius's About Page
In my humble opinion, however, the extremely well-written wikipedia entry for "Regulate" was 10 times funnier (before it got deleted), because it was using so-called "nerdspeak." Which brings me to my next point.: while some people out there really take their hip hop seriously (dead-seriously), for the rest of us there's another division or subset of rap that falls directly under the "humor" category (mostly unintentionally). Yes, there are classic comedic raps like Sir Mix-a-Lot's My Hoopty and Baby got Back, Biz Markie's "Just a Friend", Digital Underground's Humpty Dance, and Public Enemy's 911 is a Joke, to name a few.
Yet there's something about the juxtaposition of hardcore gangsta rap music against your average middle-class suburbanite that often creates a ridiculous and hilarious situation.... like Office Space's opening scene and of course, the infamous printer scene.
Lately, The Lonely Island has taken the genre of rapping white boys to a whole new level. Starting with Lazy Sunday, a rap about two guys going to watch Chronicles of Narnia, they demonstrated that you can rap about absolutely anything and everything--from Natalie Portman's life as a thug to throwing things on the ground, to being a boss, and to something as inane as simply being on a boat.
But long before Lonely Island was rapping about Jack Sparrow, and somewhere in between Vanilla Ice and Eminem, another white rapper was paving the way for future white comic rap artists. His name is Weird Al, the legendary musician who has mastered all types of music, from polka, to heavy metal, to gangsta rap, he was standing in the gap for a society that needed parodies like Amish Paradise, All about the Pentiums, and the song that neatly summarizes this whole post into a neat little package (sort of):
Update: I recently saw Jimmy Fallon and Justin Timberlake's "history of rap" videos and it definitely falls under the humorous side of rap (if anyone has a good link to History of Rap 3 please let me know, kthanksbye)
History of Rap 1
History of Rap 3
Rap Blog Series Part 1 - Asians
Rap Blog Series Part 3 - Collaborations