We think it's meant as a joke, but this page brings up an interesting question: why shouldn't the visually impaired be able to enjoy porn too? Here's one simple auditory (and tactile) solution.
Porn for the Blind (Flash w/sound @ slackcrew.com)
Update: Apparently, there's quite a demand for more of this sort of thing: "The American Foundation for the Blind reported that 22% of respondents in one survey and 9% in another were interested in watching 'Adult (X-Rated)' videos with audio description." Any volunteers?
Who's Watching? A Profile of the Blind and Visually Impaired Audience for Television and Video (American Federation for the Blind, via fawny.org)