Dirty, dirty PCs: The X-rated picture guide • The Register

http://www.theregister.co.uk/2009/11/13/ventblockers/

Well this is why I spend £30 a year on what is effectively "air in a can". The inside of my G5 is still rather shocking though - my poor baby has always suffered dreadfully from the effects of passive smoking and a laissez-faire approach to housework.