Man cave
A man cave or manspace is a male retreat or sanctuary in a home, such as a specially equipped garage, spare bedroom,media room,den, or basement. The term "man cave" is a metaphor describing a room inside the house where "guys can do as they please" like a caveman, without fear of upsetting any female sensibility about house decor or design. Paula Aymer of Tufts University calls it the "last bastion of masculinity". The phrase is thought to come from the 1993 publication, Men are from Mars, Women are from Venus.
While a wife may have substantial authority over a whole house in terms of design and decoration, she generally has no say about what gets "mounted on the walls" of a man's personal space. Since it may be accepted that a woman has input on the decoration of the rest of the house, a man cave or man space is in some sense a reaction to feminine domestic power.
Purpose
Man caves have multiple purposes: they are a place to be alone, to be away from women and from female sensibilities, to indulge in hobbies, and to hang out with male friends. It is, loosely, a male-only space to retreat to watch sports matches, or play video games. According to psychiatrist and author Scott Haltzman, it is important for a man to have a place to call his own, referring to a male area to which to retreat. Rules are relaxed; it is a place where other people's sensibilities about standards of cleanliness are not necessarily observed; as one man said, "You spill a beer there or leave a hamburger overnight, who cares?"