Weekly Monday Night Volleyball. Just come out and play! Map of the courts (google satellite/hybrid map) are at this link: http://www.google.com/maps?q=lou+neff+rd+Austin,+TX&spn=0.008803,0.015635&t=h&hl=en
You can also read here: http://www.vbref.org/austin/Sand.html (look under the first head 'Zilker Park Sand Courts').