Or so Pogue's readers claim:
...As another reader put it: “I have a Bose QuietComfort 2 headset which transforms my daily commute into almost a recreational activity. But I’ve found a better solution: Get a pair of lightweight, industrial hearing protection ear muffs for no more than $20 by Bilsom. (I love these: http://tinyurl.com/2r4a6y).”
He then suggests that, for music, you can slip a pair of regular old iPod-style earbuds *inside* the earphones. “The sound reduction is superior, there are no batteries required, it is a much cheaper solution, and the sound can be stunning, depending on what brand of earphones you buy.”
(This reader offers a video that demonstrates a similar hack: http://www.marvgolden.com/hearing/index.htm.)
This is an over-the-ear effect similar to the in-ear high end occlusive earphones. It probably won't be as good at reducing continuous noise, but it will blunt outside conversation, music, etc. Depending on what you want, this could be an advantage or not.