If you lived in Phoenix, your visiting, or your just strolling by I would check out South Mountain. They have hiking trails for just about anyone (Beginner's or not.)
The view if you take your car up to the top is still very good. You can start to see that pollution has taken a toll on the clarity, but it is not Los Angeles yet even though I believe we are well on our way. Unfortunately. Take your kids before your not able to see the whole city.