I've heard about this race for a few years from a friend. The race benefits local Boy Scout troop #39. Hence the 39 kilometers. If you'd like to try a longer distance trail race this is definitely a great race. The trails are well maintained and not technical so it's also good for a beginner trail runner.
The 39k is 3-13k loops at the Clinton Nature Preserve. If you or your friends would like something a little more tame, they also have a 10k option.

There's an aid station at the start/finish of each loop, as well as at the 7k mark. Each aid station is well equipped with typical trail race fare (cookies, chips, gummy bears, soda, water, poweraid) and staffed by cheery boy scouts and their more cheery parents. I'm not sure the volunteers understand why anyone would run nearly a marathon, on trails, in Georgia, in the middle of the summer, but they were great at keeping us happy. Each aid station also had a cooler with ice. I happily used this to soak my bandanna and hat each time through. It was even more hot and humid than usually so this strategy was much needed.

The race shirt was ok. It's a thick cotton shirt so I'll probably only use it for around the house and bed. The race "medal" however is awesome; it's a cross section of tree trunk with the logo etched on a leather cord. Very cool and unique. For the cost of registration these guys do a great job. They've made a little, local race into a very well-organized, fun event. I'll be adding this to my yearly race list.