Back in 2007 I ran my first marathon. I was new to running and had no idea what I was doing and had only trained for two months prior to the event. I did great for the first three miles but then my injured knee got worse and I hobbled the remaining 23 miles. It was one of the most painful and difficult things I have ever done. Since then I have run the St. George Marathon twice and will go at it for a third time next week. I still never feel like I'm totally prepared when I run a long race but at least I know what to expect now and I learn from my prior mistakes.
St. George is a great course and has awesome volunteers. Here is a short video clip about it.
If you have ever considered running a marathon I encourage you to look into it. Take some baby steps and give yourself plenty of time to prepare and you will be amazed at what you can do.