I went camping in Big Bend with some guys from my church in October 2010. Big Bend is in southwest Texas, right where the Rio Grande makes a big... bend. Big Bend is in the Chihuahuan Desert, so the low-lands are hot and dry. In the middle of the park are the Chisos Mountains, formed by volcanism, which rise to about 6000 ft, making the air there substantially cooler, and also gathering a bit more rain. Thus the park has a range of climates and wildlife. It also has very interesting geology.
Directions to Big Bend from Austin are: go west on I-10 until Fort Stockton (probably 6 hours). Turn left, go south for 2 more hours until the road ends. Bring your travel documents, there is a border checkpoint on the way back.
The main camping spots are in the Chisos Mountains. The view from the road is fantastic, especially going into the Chisos Basin where the camp site is, but since I was in the car I do not have any of those pictures. So the first is this very noticeabable butte, facing east towards the road into the Basin.