Rapelay, a sex game depicting rape, that was originally released in 2006 has gone viral despite criticism and bans.  The sex game, created in Japan by adult game maker Illusion Soft, has a central theme of raping women and underage girls in various locations.

Japan does have censorship laws for sexual content that require obscuring of of genitalia; they do not, however, have laws that restricts ideas or themes in games.

Officially the product is no longer available, but the company's Rapelay site is still up, and game information can be found on Wikipedia.

Link: Rapelay on Wikipedia