I read online several ways to open a coconut, and formed something of my own method. First, I drill two holes in the coconut with a power drill (this is fun), and drain the milk into a glass. I then take a heavy knife and with the blunt end tap the middle of the coconut with moderate force, being careful not to hit too hard. By middle, I mean the part you would consider to be the "weak side" of a chicken's egg. I rotate the coconut as I tap. Eventually, the coconut will split. Apparently, there's some sort of "seam" in the architecture of the coconut that allows this to happen. Next is part of another technique where the coconut halves are placed into the oven at 400 degrees fahrenheit for about 10 minutes. This allows the fleshy interior of the coconut to separate from the shell. This doesn't work perfectly for me, so I take the coconut out of the oven and give the two sides a few good whacks with the blunt end of my knife and the good stuff usually comes away easily. The result is this:
Note: Where the two halves meet is the "middle" location that I'm talking about in the above paragraph.