Zilker is fantastic. It has so much to offer, and it's beautiful too. There's lots of hike and bike trails, and it's a good place to play soccer or disc golf. They have special events all the time, like Kite Day, the Austin City Limits Fest, and especially, the Walk Of Lights at Christmas, which is one of my favorite holiday traditions. You can find all kinds of people here enjoying the nature, and many groups meet here as well.