Hottest Girls, a $1.99 app that started out with slightly risque photos of almost-naked women flipped the switch (after it was approved by Apple) to show--ahem--everything. Once the word got back to Apple, the app was dead in its tracks.
Oddly enough, when the app was first pulled, developer Allan Leung had posted a note on his site saying it had been removed because his servers had been completely overloaded. Turns out, Apple had asked Leung to remove the nude shots, or else have the app removed. When he did not comply, Apple took action.