Deem Hills Agate
Not too far from where I live, about 10 minutes by car is a hiking trail that the wife and I like to frequent during the desert winter months. Even though it's close to the city we've been able to enjoy lots of the wild life: coyotes, rabbits, snakes, quail, owls, unique bugs, and a wide variety of small furry creatures make this area home.
Soon after we discovered the Deem Hills trail, we also stumbled across an amazing agate field. Right in the saddle between two of the major hills is littered with this agate. I put a couple nice pieces in my pack, brought it home and slabbed it up. Turns out there were lots of pink, yellow, and gray swirls that took a hard polish. Much of the float is porous with lots of dirty little inclusions that makes it not so great for cutting. However, in being selective I found a few choice pieces that I've made into cabochons.
I've not seen this location written about in any of the usual rockhounding books, but it's a nice and close place to get some mid-week rockhounding in! If you're in Phoenix and want further directions, drop me an email message and I'll fill you in on the details. Note that it's about a 1 mile hike from the trailhead to the hunting grounds, but it's easy terrain if you stay on the trail.