I remember as a kid some of the conspiracy theories about how the US cut off and then classified all the deep drilling work in the late 60's [1]. I had a chance early on in the 80's to invest in a company that had designed a new drill head (one of my USC alums went to work there), I thought it was a silly investment I mean drill bits? really? But they did quite well with it.
That said, the whole concept of just digging and digging until you hit the middle holds childlike fascination for me.
[1] Mostly related to discovering alien artifacts and the like.
As am I although there is pretty damning evidence in Sonoma County [1] California that you can cause earthquakes with it. That said, I'm surprised we've not seen more closed loop systems [2][3]. My favorite is to take a loop of tungsten tubing a reservoir, a cooling tower, and a turbo pump and toss the tubing into the magma flow of a volcano. Pull out enough heat to run a turbine but not much that you freeze the lava. I'm totally going for this concept in my Mad Scientist Power Base.
That said, the whole concept of just digging and digging until you hit the middle holds childlike fascination for me.
[1] Mostly related to discovering alien artifacts and the like.