What Is a Homestar Runner

Just read a comment by an "internet" commenter who said that ADVENTURE TIME "is clearly made by and for a fairly narrow margin of 20-30 something nerds who came of age during the early aughts and watched a lot of Homestar Runner," and I was like, Ha ha, I was alive when Kennedy was assassinated and I don't even know what a homestar runner is, take that! And then I was like, Ha... ha, I'm old. And then I was like, I shouldn't connect a "ha ha" with the terrible national tragedy of the Kennedy assassination, what is wrong with me? And then I was like, God, I'm so old. And then I just sat there.