this is a great read. the details of Britney's MTV meltdown.
http://www.mirror.co.uk/celebs/news/2009/06/03/as-britney-spears-circus-comes-to-town-a-new-book-looks-at-the-night-she-went-into-meltdown-115875-21410228/

my favourite bit?

The source says: “Everyone knew it all hinged on her hitting the first line we’d rehearsed to a T – look down the camera on a close-up and lip-sync, ‘It’s Britney, bitch!’ If she could hold that line, and get through, she’d won.

“But the music started, and she stood and stared at the camera without moving her lips. At that moment, we knew it was over.”

ah, the margins are so slim...