Year zero
ISO 8601:2004 (and previously ISO 8601:2000, but not ISO 8601:1988) explicitly uses astronomical year numbering in its date reference systems. Because it also specifies the use of the proleptic Gregorian calendar for all years before 1582, some readers incorrectly assume that a year zero is also included in that proleptic calendar, but it is not used with the BC/AD era. The "basic" format for year 0 is the four-digit form 0000, which equals the historical year 1 BC. Several "expanded" formats are possible: −0000 and +0000, as well as five- and six-digit versions. Earlier years are also negative four-, five- or six-digit years, which have an absolute value one less than the equivalent BC year, hence -0001 = 2 BC. Because only ISO 646 (7-bit ASCII) characters are allowed by ISO 8601, the minus sign is represented by a hyphen-minus.
Year Zero (video game)
Year Zero is an alternate reality game (ARG) by American studio 42 Entertainment based on the Nine Inch Nails concept album of the same name, its expected follow-up, and a possible accompanying film or television project. Although the album was released on April 16, 2007 in Europe, and the following day worldwide, the game had been underway since roughly February 12, 2007 and was expected to continue for approximately eighteen months. The game was created by 42 Entertainment, the same group responsible for the "Halo 2" promotional alternative reality game "I Love Bees". Trent Reznor, frontman and sole member of the band, has called the game "a new entertainment form". In response to criticism regarding the promotion of the album, Reznor stated: