Brooke ate the "Yomi-Yomi" fruit [presumably 黄泉, the underworld]. Until he died, he just couldn't swim, but once he died, he had the ability to come back to life a single time.
A number of decades ago, when he was a pirate, someone massacred him [and his crew] in the Florian Triangle. His soul managed to find his dead body, but because it took a year, it had been reduced to bleached bones. However, his roots were strong so his afro remained the same as ever. Before he died, he was a musician. Being undead, Brooke has no reflection in the mirror, casts no shadow, and disappears when hit by sunlight.
(He tells them all this over dinner.)
This week, a ghost appears behind Zoro in the room. When they go outside, an island is visible that the Log Pose doesn't respond to. Brooke explains that it's a ghost island he's been searching for, that appeared through the fireworks (?) in the barrel. He doesn't recommend landing there, but because he apparently wanted to see it again, he runs across the surface of the water to the island (since he's just a skeleton, he's light). Luffy, starry-eyed, wants to go to the island.
's it for this week; original poster wrote all he could remember.
Interessante Randbemerkung von Prince: Was mir beim genauen Lesen des Original Spoilers kam, ist, dass Brooke erklärt, was passiert wenn er mit Sonnenlicht in Berührung kommt: Hierbei verwendet er das Wort 消滅 (Shômetsu). Dieses Wort hat eine viel stärkere Betonung als nur "verschwinden", es wird häufig im Zusammenhang mit Tod verwendet, da es auch mit Aussterben oder Erlöschen übersetzt werden kann.