Jojo's Bizarre Adventure is an epic manga spanning across generations that started in 1987. Each "part" of the story (there are currently 8), focuses on a new descendent of the Joestar family line.
Parts:
Part 1
Phantom Blood: Volumes 1 to 5
Part 2
Battle Tendency: Volumes 5 to 12
Part 3
Stardust Crusaders: Volumes 12 to 28
Part 4
Diamond Is Unbreakable: Volumes 29 to 47
Part 5
Vento Aure Volumes: 47 to 63
Part 6
Stone Ocean Volumes: 64 to 80
Part 7
Steel Ball Run Volumes: 81 to 104
Part 8
JoJolion: Volumes 105 and ongoing
Anime:
A Jojo's Bizarre Adventure is set for October, the studio, cast, and other details have been announced so far.
OVA:
Jojo's Bizarre Adventure has an OVA set in the 3rd arc with the second half of the arc being animated in the early 1990s and the first half in the early 2000s.
Movie:
A movie based on the first arc (Phantom Blood) was shown in Japan, but Araki stopped it from having a home release.
Video Games:
Jojo's Bizarre Adventure (PS1-DC-Arcade-PS3-360)
The Jojo game everyone knows of, a fighting game that covers the third arc.
Jojo's Bizarre Adventure (SNES)
A RPG that loosly covers the third arc.
Le Bizzarre Avventure di GioGio: Vento Aureo (PS2)
A PS2 action game set in the 5th arc.
JoJo's Bizarre Adventure: Phantom Blood (PS2)
Another action game, but this one focusing on the first arc.
Jojo's Bizarre Adventure (PC)
A fan made Japanese RPG Maker game for the PC that follows the third arc.
JoJo's Bizarre Adventure: All-Star Battle (PS3)
An upcoming "fighting game" by Cyberconnect2 that will have characters from arcs 1-7.
Links:
JBAcommunity - A great Jojo forum
The official site for the anime
Araki-Jojo - "Official" Jojo news
The Namco Bandai site for All-Star Battle
Jojo figures
Jojo statues
Rules:
No untagged spoilers
No insulting poses