Alright. I'm gonna say it. I don't get why this is so damn popular. It's interesting, and it looks cool; I'm not saying it's bad at all. But the blood and gore has been done before in things like Blood and Ninja Scroll. And the hip hop samurai stuff has also been done, and done better in my opinion, in Samurai Champloo. So all Afro Samurai really has going for it is Samuel L. Jackson, a so-so plot full of holes, and it's unique animation style.
Afro Samurai follows a samurai called the Afro Samurai (bet you didn't see that one coming) on his journey to avenge the death of his father. In this futuristic (with feudal elements) view of Japan, there exists a person known as Number One, the best fighter in the land. Once Number One claims his title and near god like status, he waits until the day the Number Two comes to take the title away. Only the Number Two has the right to challenge the Number One, so the Number Two's journey is filled with fighters attempting to take the title so they can challenge Number One. These titles are represented by sacred headbands depicting the warrior's number.
In this story, Afro is the Number Two. The Number One is a gunman named Justice who killed the previous Number One, Afro's father, when Afro was a small child. Afro devotes the rest of his life to training with his father's sword in order to find the Number Two headband so that he can go after Number One (Justice). And that's basically the whole story. A good chunk of the 5 episode series is made up of flash backs of Afro as a child training in a dojo. It is in this dojo that he meets the young girl Otsuru, the Sword Master, and the young man Jinno. They all have roles in his future life. The Sword Master trains him, and both Otsuru and Jinno reappear (as opposition) during his journey to defeat Justice. As Justice makes very few appearances, most of Afro's trouble comes from a group of monks called the Empty 7 - six monks who are trying to defeat Afro so they can kill Number One and have the power of both headbands. Keeping Afro company and offering him tactical advice is Ninja Ninja, an enigmatic character who seems to be some sort of spirit, or possibly a figment of Afro's imagination.
It's not a bad show, but I don't really get why it's such a pop culture phenomenom. I'm sure Sammy L. (who does an excellent job voicing both Afro and Ninja Ninja) helps; after all he's a culture phenomenom all on his own. I certainly don't feel like I would be missing out if I hadn't seen it. Which, if you haven't noticed, is my way of saying "It's a decent watch, but nothing to get uppity about." The RZA (Kill Bill) did the music. It IS really well animated, and has a very distinct and unique style. Though it strikes me as odd that casual fans (or people who aren't anime fans at all) enjoy the artsy look of the show. Though I'm sure the rather graphic and completely unnecessary sex scene helps.
FUNimation has released two versions of the show on DVD. A "Spike TV" cut, which I guess is the edited for TV version, though I'm unsure why anyone would want that. And the "director's cut" which is unedited. There's also a recent sequel called Afro Samurai: Ressurection, in which some people who died are ressurected so that they can die again. Hooray.
There's also a video game.