Mark those calendars! On June 5th 2012, starting at 5:09 PM EST (22:09 UTC), the orb of the planet Venus will cross the face of the sun in what is known as a transit. The last this happened was in 2004, the next will be in the year 2117!
Image Credit: Robert J. Trembley. 2004 Venus Transit. 8″ Orion Dobsonian & Nikon Coolpix