Most often, hip-hop covers bring to mind images of indie bands rapping something that could be found on one of those Now Thats What I Call Music compilations, with their tongue firmly in their cheek. Well, that's not quite the case here. For this Friday Five, I've gathered a collection of songs by hip-hop artists that are covers of non hip-hop songs, not just samples for production or rehashed for their hooks. It took a bit of digging, but I was able to find songs by the likes of Mos Def and Ol' Dirty Bastards that cover such classic artists like Nina Simone, Michael Jackson, and even 80s sensation A-Ha. Some of these tracks are pretty standard covers; others are more like remakes, keeping the theme of the original or flipping it to examine the idea from a different angle. It is interesting to consider how a genre like hip hop -- indebted to music of the recent and distant past for its foundation -- doesn't quite practice the art of covering nearly as much as other genres. It could stem somewhat from the fact that hip hop has this often-regurgitated notion of being a very personal genre; the performer is almost always assumed to also be the author (even though hip hop employs songwriters probably almost as frequently as other genres, just much more secretly). Another part of the reluctancy could be due to the fact that hip hop is not a genre where performers are necessarily considered good vocalists, and therefore a cover of another's material could lose some value to the listener. Well, while you ponder your own theories of why Jay-Z has yet to record his own version of Billy Joel's "Piano Man," enjoy a bit of inter-generational and inter-genre experimentation with this edition of our Friday Five.