Climb up the back side of Camelback Mountain to its 'hump'. This is a great place to hike, but there are some difficult areas. Much of it after the first half-mile gets very steep and rocky. Don't try this if you're a beginner--getting down is much harder than going up.
There's a water fountain at the bottom but no facilities on the trail. Once at the top, you have a great view of Phoenix and the surrounding vegetation. The hike takes about 2 to 3 hours, depending on your level of expertise and the other hikers in front of you. Parking is very limited, and on weekends, you may have to wait a while to park. Between the months of October and April, anytime is a good time, but in the summer months, don't try it after 6 or 7 am--it's too hot outside.