Monoprice Microphone Isolation Shield
The room I record my podcast in at work is fairly small, but it has concrete walls. I'm not an audio engineer, but even I know that audio and concrete don't mix. I considered building a contraption to shield my mic using foam and a large box, but then realized that someone probably is selling exactly what I want. A quick search on Amazon resulted in quite a few options. I ended up choosing the Monoprice 602650 Microphone Isolation Shield.