I'm looking for a duct.
Kind of like this one: http://www.1coolpc.com/ductingmod.htm

But I need it to be 90 degrees and it doesn't need to have mounting holes on the outside side of the vent... just a vent up.

Here's what this is for... our new appartment has nice freshly painted walls, I don't want to put 5 computers blowing their fans directly back at the wall. Last place we were in, the wall was black back there. h:

 

Is this going on top of the CPU? I'm having some trouble trying to visualize what you're trying to do.

 

If the wall under the desk isn't particularly visible, you could always like, tape some paper up to the wall to catch the dirt.

 

I believe he wants to stick snorkels on the outside of the back of his computer so the fans blow air in some direction other than directly towards the wall.

Like such:

 

yes, very much like that... except upwards, but esentally yes.

I didn't realize how dirty that wall was untill I moved.

 

That's what I thought he might want to do. Why don't you just make a hood out of some aluminum? It doesn't have to be round does it?

:EDIT: You could do something like this, only out of metal, or cardboard like this guy. http://forums.pimprig.com/showthread.php?threadid=19007 Near the bottom.

 

haha, that's ghetto... but it probably works good enough.