Not sure if anyone's suggested this before -
Dead PCI card (well it's dead now). Hole's been cut with a Dremel.
White blobs are UHU White Tack (softer than Blu Tack IMO)
Side view
First thought of this when I had a fanless card - it was getting a bit too hot for my liking.
Now I use this cooling method for graphics cards with active cooling - I just remove/unplug the fan. I only have low end cards (currently have 6600 + 6610 so not sure how the cooling method will work with high power cards).
Another idea - not as good as the one above as I could feel vibrations on the PCI plate/green PCB.
Edit: Solution For High Power Cards - LOL (this is someone else's idea - can't remember where I saw it though)