'Mohorovičić discontinuity' is the coolest thing. I learned about it from Total Annihilation, which leads me to believe that anything to do with tapping the mantle is awesome.
Yes, moho is badass.
Also, things start to get really hot at that point. To be honest, you'd need something like Adamantine to drill into the mantle, because, well, the pressure and temperature is so high anything we currently have would be destroyed in a few minutes at best.
It's not the temperature; the mantle is between 500-900 °C. Steel melts at about 1370 °C depending on the alloy. It's the pressure that kills you down there.
Speaking of, it sounds like a lot of you seem to be under the impression that the mantle is all molten magma. Not so. While the temperature is high enough to melt most of the mantle-rock at sea level, the pressure raises the melting point of the rocks pretty far above that. The mantle is almost entirely solid.