Venus transits the sun on June 5th. The next one will not occur for over 100 years! For those with solar filters, you can photograph it directly. For those without solar filters, you can watch the transit by using the projection method.
Starts around 6:00 pm on the east coast.
Don't miss June's rare transit of Venus - Astronomy Magazine
Transit of Venus: June 5–6, 2012 - Homepage Observing - SkyandTelescope.com