Metal Masher, Steel Bender, Kane Creek, leading Elephant Hill, and Flat Iron Mesa. Basically all reds except what I'm leading.
One thing that Kevin and Josh are doing this year (and maybe they've done this in the past) is let the trails increase in difficulty within their color range as the week goes on.
My personal experience started with Hell's Revenge - first trail I ran out there. After that I did Seven Mile Rim, Fins, Hell's again, Elephant Hill, and then closed with Poison Spider Mesa. For anyone who's having their first time out there, read the trail descriptions and go with what you're comfortable with. If you want, start easy and work your way up. However, prepare to be amazed at what your X can do. You'll climb hills you never thought possible, see some incredible sights, and have fun with folks.
However, you don't necessarily have to start easy. Obviously I didn't and I'm alive and didn't do a bit of damage to the X when I was there.
YMMV.