My house has a built in entertainment center, with shelves on either
side of the TV. These shelves are 12" wide, which is way too small for
DVD and satellite receivers, etc. So I need to place the items in the
built in cabinents below the center. Even with the doors removed, it
is getting way too hot in the summer in this enclosed space (the wall
behind the entertainment center is the garage!). The new electronic
equipment coming out these days generates insane amounts of heat (XBOX
360 I'm talking to you).

I want to place a 6" or 8" duct to pull warm air out this cabinent
space with a fantech inline duct fan. My question is: Where do I take
this warm air. Do I need to route is back to the return air duct to
prevent negative pressure? Can I vent this to the attic, and perhaps
enough air will find it's way in to the house? Or could take it
through the back into the garage as well. Does anyone have a
suggestion for a solution. Thanks in advance!