I believe I watched this cartoon series around 2006 - 2008 I am not too sure.
There is 3 characters. Two boys, one girl. I only remember what one of the characters looks like. He was always weard red/blue 3D glasses, and I think he was the tallest in the group. (I'll link a drawing of him I made from my memory, down bellow). I think the other boy was short and had black hair, more emo, gothic looking? I have don't remember what the girl looked like, but I know she was part of their friend group.
The setting had a ghost, paranormal feel to it. All I remeber one episode is that they went to a big graveyard, and they go inside one of the graves. (like the grave is kinda like a house with stairs to go downstairs to the coffin). That is all I remember.
I don't know if this cartoon is American, I live in Norway, so it was dubbed to Norwegian. But it could honestly be from any country. I've also checked through cartoons that have aired on nickelodeon, disney channel, fox kids/jetix and cartoon network without any luck.
drawing of one character from my memory: http://i.imgur.com/HTA4V9m.png