Willcox Playa, aka, the salt flats, aka Arizona Beach (English for playa), is located in the southeast corner of the state, about an hour to the East of Tucson, AZ.

How to get there: Hop on I-10, heading East from (or past to the West of) Tucson or West from (or to the East of) Willcox. When you hit Exit 331, leave the freeway, and you'll be you on southbound US 191. After around 4.0 miles you'll have just passed over a long bridge, and to your right will be a visible turn-off, and to the left will be a harder to see descending dirt road. Take the dirt road. Turn left (you're not going into the military reservation), and follow the path up to and then alongside the train tracks. After maybe a half mile you'll see a sign that warns of ammunition duds ahead. Turn in here, and soon the shrubbery will clear. You are now in a huge, plantless, flat area. Congratulations.

What's there: Nothing. Almost. My travelling companions assured me that the ground does taste like salt, so there's lots of that. Vehicle tracks abound near the entrance, so it's not completely improbable that you'll see some locals recreating there. Off in the distance, you can spot some kind of factory, spitting out smoke. A couple miles from the entrance there are three cement cylinders, about 5 feet tall, arranged triangularly, with pipes sticking out the top. There are at least two similar configurations of cement cylinders, spaced a couple miles apart in other directions. What are they for? I don't know. One of the cylinders has a colony of bees sitting inside it, although apparently they're dormant enough during the middle of a summer day to not be interested in harassing humans that invade their space and lean over the cylinder to look inside their pipe.
Update: I went again, this time as the sun set, and managed to see (after much more driving and much less walking) a four by four sticking about three feet out of the ground, a bat, and a pyramid (about knee-height).

Should I go? Only if you're into novel natural landscapes. Otherwise, your short attention span may drive you into restlessness, and this will soon spawn anger at all that time you wasted driving there. If you've visited either of the salt flats in New Mexico, I'm told that the Willcox Playa is more impressive, easier to get to, and less visible from the freeway.

If you go: If you've been looking for a place to try stupid car tricks, here you can go hog wild. But don't do anything so stupid that your car gets disabled, because it's a pretty long walk to the nearest tow truck. As always, when in Arizona, bring plenty of water. Also, don't ditch your footwear in a foolish attempt to prove how rugged you are. I, after ditching my footwear in a foolish attempt to grow thicker callouses on my feet (they've grown softer over the summer, when I can't walk barefoot much because the ground is very hot), found myself in the worst pain of my life after two or three miles. The ground is covered with lots of bumps, which feel deceptively fine at first. Maybe a geologist could tell you why or how they're formed. I can only tell you that after finally getting back to the place where I'd left my sandals, I cried out (perhaps the only time the phrase has been said in earnest), "It feels like I'm walking on a cushion of air!"