Transit of Venus
For North America: Afternoon of June 5th
Once in a life time. Venus passes in front of the Sun. Next Venus transit: Dec. 2117.
Protect eyes when viewing Sun.
Eclipses 
Solar Eclipse (annular)
May 20, 2012
Partial eclipse visible in California
Lunar Eclipse
Jun. 4, 2012
Partial eclipse visible in North America
Solar Eclipse
Nov. 13, 2012
Not visible in North America
Lunar Eclipse
Nov. 28, 2012
Partial eclipse visible in North America
Meteor Showers
Jan. 4 Quadrantids
Apr. 22 Lyrids
May 6 Eta Aquarids
Jul. 29 Delta Aquarids
Aug. 12 Perseids
Oct. 8 Draconids
Oct. 21 Orionids
Nov. 17 Leonids
Dec. 14 Geminids
Typically, the Perseids and the Leonids are the best showers of the year. The Geminids may also be a good shower to watch.