For those who really like their privacy, consider taking a look at the Danbocchi. The Danbocchi is $500 cardboard box that is intended for those who value their privacy and/or choose not to disrupt others around them. The purpose of the box is not only for isolation within your home, but to dampen noise at a certain measured soundproofing.
The Danbocchi was originally created for the purpose of dampening noise made by those who wish to play video games or sing loudly in other parts of their home. The target market was for those who do not wish to disturb neighbors or the like after pursuing certain loud activities. Take for instance those whom live in a townhouse or apartment; the Danbocchi is made to substantially lessen this noise.
The Danbocchi is soundproofed for up to 30 decibels meaning that if someone was singing at 90 DB, it would only sound like 60 DB -- which is about the normal speaking volume. This $500 box is available for purchase online.