On the year of my birth (1988) Hirohiko Araki, a Japanese gentleman blessed with immortal life
, took up a great labour. He would write a shounen series that would span over 2 decades, 7 protagonists and 96 volumes. It is still going strong to this day.
What follows are very, very brief summaries;
Jojo's Bizarre adventure (JJBA) started life as a rather ugly series, set in 19th century London about a young man mountain, Jonathan Joestar and his struggle with the evil Dio Brando, and equally beefy vampire. Over the journey the art would become better, Jojo would learn the martial power of the ripple (aka: Hammon) from the stylish William Zeppeli and hang around with the oh so useless but lovable R.E.O Speedwagon. Friends were lost but evil was slain at great sacrifice... or was it?
The second arc covers Joseph Joestar's adventures in 1930/40's Italy and South America where he learns to master the ripple and with the aid of Zeppeli's grandson and a mysterious woman who is totally not Joseph's mum fights a group of super beings who are to vampires what vampires are to humans. These were the guys who made the mask that turned Dio into a vamp.
By part 3 (I think were in the 80's now) Araki got tired of the ripple, which, if we're honest, was just a ripoff of Fist of the North Star. We now introduce "Stands" which are manifestations of a persons Will and spirit. The new Jojo to take the lead is Jotaro Kujo and his quest to put an end to Dio who has recently reappeared (having taken over Jonathan's dead body.) His quest takes him across the globe, from Japan, through Asia, into Egypt with many battles with stand users along the way. In the end Dio is finally put to rest.
At this point Araki could have called it quits and you can to if you read it but that'd be silly.
Part 4 roles around (late 90's) and is more of a side story. Jojo of the day is Josuke ("suke" can be read as "jo"), illegitimate son of Joseph but younger than his nephew Jotaro, and the strange people he encounters in his town. Most are stand users, some are even strangers, some are enemies but most become friends after a while. The main plot of this arc is to find a murderer who's been at work for over 15 years. The art by now is unrecognisable compared to the original.
Part 5 is another side story set in Italy and follows Giorno Giovani, one of Dio's sons and his attempt to take over a mafia family and turn into a kind of Robin hood group. I've yet to read this so there's not much I can say.
Part 6 has out first female Jojo and daughter of Jotaro, Jolyne Jotaro, her time in prison and her attempt to stop on of Dio's followers, Father Pucci, from rewriting history and creating his own perfect world. Sadly things don't quite go as planned. The day is lost but Pucci's plans are not fully realised either. This is technically the end of Jojo. However...
Part 7 is still going right now (and has apparently jumped from Shounen to seinin if that matters to anyone) so you can find out about that yourself. All I'll say is alternate universe (due to Pucci rewriting time) and we're back in the 19th century.
This is a long running shounen series and each part has it's own unique style. There are tons of references to music bands, Italian fashion and food and a focus on being smarter than the enemy rather than stronger (although most things do end up in a good ol' punch up.) It's not deep or intellectual but it's funny, imaginative and enjoyable.
If you just want the main plot then read part 1, 2, 3 and 6 but it's worth reading it all.
Only Part 3, Stardust crusaders, is licensed but it is on hiatus due to some controversy about possible offence to Islam. A 13 part OVA series was also made and licensed for this part but is also under investigation for using pages of the Koran in a book for one scene. Oh dear.
A movie was made for part one but subs (and even raws) have yet to surface and it seems doubtful they ever will.
The rest is unlicensed and fully scanlated for you to find. Be warned, a good amount of the scans for parts 3 and 4 are pretty low quality with some of part 4 being laughably bad. It's worth going through though.
Part 7 is still going but scanlations are fairly slow.
The way I've described it makes it sound like a generic fighting shounen with a fairly neat gimmick but (and I guess all fans of any shounen say this) this series is well written, nicely paced (apart from part 3 which is rather drawn out) and the art is great once Araki gets into his stride.
If that big wall of text was to much or you want a bit more then check out these links;The Wiki article.
There are separate entries for each part. (spoilers, duh.)ANN manga pageANN Anime pageOne of my award winning posts on the evolution of Jojo's art.The TVtropes page.
(spoilers)People trying to do some of the famously flamboyant "Jojo poses"
Fanart is from http://www.pixiv.net/
(there's a guide to registering on DevArt)