Maybe you bought a condensor microphone for the clairity and you now notice that this mic picks up EVERYTHING. Well here is a tool that can help you cut out the background noise. I've seen different varieties of this type of soultion. This is the first one I've seen for $99. Please note: I have not used this item. I only post this for your awareness.
Here is the description: The Primacoustic VoxGuard is a high performance ambient noise attenuator designed to mount on a microphone stand & surround a recording microphone to help control the sound from entering the microphone by minimizing the reflections in the room. Made from lightweight, high-impact ABS plastic with a high-density open cell acoustic foam liner, VoxGuard fits onto a mic stand using the mic clip to hold it in place.