Rock song question?

whats that song called in the music there some couple getting married then she leaves him for some dude outiside and the people r all in clowns face
its a rock song

are you talking about the panic! at the disco song?

I write sins Not Tragedies

http://youtube.com/watch?v=vc6vs-l5dkc

...Panic! At the Disco -- I Write Sins Not Tragedies.

That's all I can think of.
It's pop-punk..

I Write Sins Not Tragedies - Panic! at the Disco

I Write Sins Not Tragedies
by
Panic! At The Disco


Maybe?

I Write Sins Not Tragedies by Panic! at the Disco

that is Panic at the Disco i write sin not tradgides
and it is rock