These days, the line between mixtape and album is thinner than ever, and fans are fairly entitled when it comes to new music. As a result, we're seeing more and more projects being released in a shorter time frame, but there are only a select few who can impress both in terms of quantity and quality. The "run" is something a few artists have been praised for. It's generally a series of projects that mark an important creative spurt for an artist, and one that often creates something of a spectacle. With that being said, some "runs" get a lot of publicity, while some fly under the radar. Today, we're looking at both artists that have been defined by their prolific bursts, and some you might not have been paying close enough attention to. Many of them are still going. Click through the gallery to see the artists that impressed us with their output.