Sex partner: Each other
Year it leaked: 2007
The tape was made in 2004, when singer Ray J was (we are told) more of a celebrity than Kim. By the time it was leaked, Kim had her own TV series, and any theory that it might do Ray J's career some good went out the window. Vivid Video released the footage as Kim Kardashian: Superstar; Kim sued to stop its distribution but ended up quickly settling for $5 million. 

Real or fake?: Real