This is Fall Astronomy Day & Night in conjunction with the International Year of Astronomy 2009 Cornerstone Project Galilean Nights to observe Jupiter, our Sun and Moon:
http://www.galileannights.org/
Public nights on Mount Tamalpais start with a lecture in the Mountain Theatre, followed by public viewing in the Rock Springs parking lot. SFAA members may view privately after crowd departs, approx. 11 pm-2 am.
For more information go here:
http://www.sfaa-astronomy.org/starparties/