Post Rock is a different kind of rock music that is still associated with the rock esque kind of feel, but has a more mellow feeling to it. Bands like Sigur Ros and Explosions in the Sky are two bands in the Post Rock genre.
Thank you Last.Fm!
Okay I have some experience with Sigur Ros, I always thought they were an experimental band that sang in their own made up language...Hopelandic I think it is called. You learn something every day if you pay attention seemingly, thanks Under.
Sigur Ros i think they fall under many genres, maybe you are right on that LG, but they can also fall under Ambient with the uniqueness of the hopelandic lyrics they make which btw you are right about the language. a lot of bands are that way, Linkin Park for example, they are Metal, Rock, Punk Rock and Nu Metal