This is a free event but they do ask for donations at the door. You may bring your own chairs and blankets but no food or drink. However, these items are sold at the garden (bring cash). I believe parking is free but limited.
The doors open at 6:30 p.m. so try to get there early to get a close seat. The performance starts at 8 p.m.
I went to this last year and really enjoyed myself so I hope many of you will be able to make it out.
Link to a summary of the "Tempest"
http://www.about-shakespeare.com/tempest.php
Botanical Garden web page
http://www.sabot.org/?nd=home