Def Jam Rapstar, like most modern music games, has downloadable songs. Def Jam Rapstar, unlike any other modern music game, lets you download Paid in Full or Passin' Me By. Rap classic, $2 a pop. Here's the official list:
That's the DLC for the year's only rap karaoke game that has been issued since launch earlier this month. There are some greats in there. You can rap to them (or butcher them as some do) — or rap over the extra freestyles offered.