I usually cut it in half (through the equator) and eat it with a spoon but the juices tend to spray everywhere.  Is there a better way? 
Grapefruits are one of my favorite fruits, and you can get around the entire process by just tossing the whole fruit in a high quality juicer... then you can drink it and never have to worry about spraying yourself (unless you accidentally spill!)  You can go further by adding other fruits like strawberry or grape and even some vegetables with low acid content (so the fruit will overpower the taste of these) and make yourself a very tasty and healthy beverage. 