One evening I googled to find out an easy way to open a coconut and remove its meat.  I've found a lot many ways and the best way, which I found, is:
  1. Inspect the coconut. Usually coconuts will have some dark areas on them. About the size of the dime, there are usually three such areas. These are the weakest points of the coconut. Using that area's weakness, it's time to break out the hammer!
  2. Nail the coconut. Literally. Lay out your towel and place the coconut on top. Then using your hammer and nail, nail into one of the weak spots on the coconut. Don't drive the nail all the way. Just enough so that you feel it break through the shell to the hollow middle. Remove the nail.
  3. Drain the coconut. Next place the coconut over a short glass or bowl with the hole side down. Let the coconut drain for 3 minutes or so. If you wish you may drink the coconut milk, or save it, and make drinks with it. (It's quite tasty with rum!)
  4. Place your coconut back in the towel. Now it's time to take out some aggression! Once in the towel, take your hammer and strike the coconut forcefully. This may be best done on the ground or on pavement, as you will need to strike it quite hard and you don't want to ruin your counter top. Continue striking the coconut until you feel it break. You may continue to strike it a few more times until you have broken it into several pieces. This make it easier to grate or remove the "meat" of the coconut. 
  5. Use your knife. This is an alternate way to break a coconut and perhaps a tad more impressive in front of your friends. But it should be noted that this is not for children to try. And if you feel your child is old enough, be sure to supervise them closely. Take a heavy cleaver knife in one hand and the coconut in the other. Then rotate the knife so that the BLADE IS FACING UP, AWAY FROM THE COCONUT, and strike the coconut with back of the blade. It will probably take several forceful whacks as it did with the hammer. Also be sure to strike the coconut in the center. This will keep it from flying out of your hand and also distribute the most amount of force throughout the shell.
  6. After breaking the coconut open, you can bake it at 350 degrees for about 15 minutes and the meat should come off the shell rather easily.