Won't Start.

My jeep has been running like a champ for 7 months now. On 8-14-11 at apprx 7:30 I drove started and drove my jeep about 300 ft. And parked on a slight incline with the front facing up the incline. After it sat for less than 30 min. It would not start. However it does have a full battery charge. Thinking it had something to do with the incline I pulled it up to level ground. I tried turning it on in park and in neutral. Still wouldn't fire. Once I got the car towed home I removed the Starter, and had it tested. It was fine. I checked most of the fuses (under the hood, and the the smaller ones in my passenger side panel). They were all good. At this point I'm at a loss. I don't know where to go from here.