In 2009, composer/lyricist/performer Lin-Manuel Miranda performed an amazing hip-hop piece about Alexander Hamilton (5-min video, with mostly-accurate captions) at the White House. He said at the time that he was working on a concept album about Hamilton; since then, it's turned into a musical, Hamilton, which will apparently be moving to Broadway in July.
There's a long New Yorker article about Miranda and Hamilton; I've only skimmed it, but he sounds like an interesting guy and the show sounds great. Hope I get to see it at some point.
In the meantime, to further whet appetites, here's a John Adams rap that was apparently cut from the show. (1-min video)
(Thanks to Susan and Marguerite for introducing me to this.)