I was blindly connecting the mic and output jacks to the back of my soundcard and I accidently plugged in the output jack into the line in insert and I started hearing sounds as if I plugged in my mic, but instead it was all low frequencies and was a bit quieter, it also had very little feedback. I played around with this a bit and had the sound come out of my speakers and input from my headset's output. If I turned the volume up or down on the volume controller on the headset, it would get quieter or louder.

My headset is essentially two mics!! :D
This sounds very nice for beatboxing!!!!!