I just downloaded it again from myself and the new copy worked fine.
EDIT: Lulzsec created a ZIP file, but changed the file extension to RAR. Doh ho ho, those wacky guys. Your unrar tool is apparently more fragile than WinRAR, which decompressed it without even throwing an error.
Since I want to preserve the filename, I made a copy:
http://bbot.org/Fuck%20FBI%20Friday%20(FFF).rar
The IRC log is really damaging... assuming, of course, that Lulzsec hasn't embellished it.
EDIT: The archive is actually a ZIP file, with a RAR extension, which makes some decompressors unhappy. A copy with the correct extension:
http://bbot.org/fff.zip