It's a rap. About Arlington.
Hat Tip to the Raveler who first provided this link.
And just for a complete contrast. The above may be the first rap about Arlington, but it is not the first song.
Emmett Swimming also has one*.
In the interest of completeness, there appear to be a number of songs titled Arlington. But most of them appear to not really be about the city itself.
*Sorry, embedding is disabled on this one.
Edited to add, I only just realized that DCist posted very similar links. I swear I came to this other ways, but great minds and all that.