What is Roflganger?
1.
A persons exact laugh double.
Someone who has the same distinctive laugh as you.
(like doppelganger)
Person 1: Is that Roy I can hear laughing?
Person 2: It can't be, he's on vacation.
Person 1: Wow! That's totally his roflganger!
See
2.
an extension of the word
Dude: So I'm at this party and Jason was wasted and he fell through the bathroom door with his pants down!
Guy: ROFL!!
Dude: Then, to make it worse, he shit his pants on the way home in Rachel's car!
Guy: ROFLGANGER!
Dude: Guy, you are so retarded. Why do I talk to you?
See