I love how random recipes happen when you're hungry. I started making this when I was nine and have changed it over the years. This is my favorite, not to mention healthiest, version.
1/4 - 1/2 cup whole coconut milk (up to you, depending on how creamy you want it)
1/2-1 cup crushed ice (again, up to you on how much you want)
Combine all in blender and blend to desired texture.
Drink and enjoy!
Additionally, you can always add other yummy things like raspberries, to make this your own special blend of yumminess. That may not be a word, but I like it anyway.
A little side note on the coconut...
When I was studying nutrition in school my teacher informed of us a research program going on in regards to coconut curing aids. Yes, curing aids. A gentleman was given three months to live and decided he would go live it up in the tropics. Everything he ate and drank while there contained coconut. Three months later he was alive and well and went back home. When his doctors checked his vitals they discovered no signs of the HIV virus in his system. After questioning him thoroughly they came to the conclusion that the anti-viral properties of the coconut, having been consumed in large amounts, must have somehow healed him. There is research being done on this, but it is a very quiet topic. If I am recalling this correctly, the article should be on pubmed.gov.
Additionally, you may have heard over the years that coconut has a bad rap for the fat content due to a study that was done ages ago making it out to be the bad guy. Later a new study was done finding that the prior research was faulty and that coconut is in fact ridiculously good for you. I can attest to this personally. Coconut milk is anti-viral and anti-bacterial. It kills canker sores, kills tummy bugs, and is a safe fat to add to creamy recipes. Coconut oil is fantastic for dry hair and skin, not to mention wonderful for cooking with at higher temperatures. Coconut water helps maintain pH balances in the body and is a natural isotonic. I prefer the C2O brand and am very seriously considering taking stock in it. I may have a little coconut addiction actually, but I'm willing to admit that.