Gar = gay, usually to say you're gay for something. It originated from a typo. I found a good definition that fits both of us, though.
A term used towards male characters and individuals who are so overwhelmingly manly that your own masculinity is absolutely *buried*, leaving you naught but a whimpering, swooning girl-child before them.
Originated in 4chan's /a/ board. A poster was describing his feelings towards the Fate/Stay Night character Archer, and mistyped "gay" as "gar".
http://www.urbandictionary.com/define.php?term=gar