Doppelginga 

When one redhead is mistaken for another redhead due to simply having the same hair colour: actually looking alike is not necessary. Can also apply in situations where two unrelated redheads are assumed to be siblings due to just having the same hair colour.

Despite having distinctly dissimilar facial features and dress sense, Mary was often mistaken as Jane's doppelginga.

Doppelginga by mythily August 10, 2009

doppelginger 

What you call one red-headed, freckled person that looks exactly like another red-headed, freckled person that you know. These people are often mistaken for each other, and hilarity ensues. Everyone in Ireland has at least three of these.

Normal Friend: Hey man, you didn't wave at me when I saw you on the street!
Ginger Friend: I don't think that was me...You must have seen my doppelginger.

doppelginger by Mekhallama February 12, 2013

doppelbänging 

Having sex with yourself through the creative use of a time-machine.

Twilight is so gay that in order to be gayer, you'd have to be discovered with a time machine, doppelbänging yourself.

doppelbänging by Seapoo June 9, 2010

Dopplebanging 

The act of hatefucking a person for no reason other than that said person bears a passing resemblance to your ex.

"I got so drunk last night, I wound up dopplebanging a Starbucks barista against a vending machine"

"I'm so sorry I dopplebanged your mom"

"Paul just got dopplebanged"

Dopplebanging by Amiahipstermaybe December 5, 2011

Doppelginger 

An alcoholic drink made from Gin and Ginger Ale.

"I don't know if I want a gin and tonic or a doppelginger"

Doppelginger by WPTaylor4 May 21, 2010