See, my little brother is in college working with lasers to get himself a real job, but it's a lot of fun when our respective disciplines overlap, even if just a little bit.
He had to build a chamber that could reduce external vibrations for sensitive equipment inside, and asked me about acoustic treatments like foam. I of course go through my spiel about the difference between shaping reflections in a space, and absorbing sound, preventing it from leaking into or out of a space. I then sent him some info on Owens Corning and like insulation.
Billed as an alternative to mass loaded vinyl, QuietRock looks like it could be a good solution for those that have to use an existing structure. When paired with other treatments like insulation it looks like it can provide substantial attenuation across a wide spectrum of frequencies.
You can find more info at: http://www.quietrock.com/quietrock-drywall.html