On 05 June 2012, the planet Venus was in transit across the face of the sun. That is to say, its orbital path passed between the Earth and the Sun at a planar level where we could see its shadow.
The image above is from a live webcast from the NASA EDGE (link probably good until around 9:30 pm PDT) project at the Mauna Kea observatory in Hawaii. It was captured about an hour in to the event. (I have rotated the image 90° counter-clockwise, because I believe that is the orientation we would see from the Northern Hemisphere.) For a slightly different perspective, here is an image captured about 2 hours into the event, from the SLOOH Space Camera project via the observatory at the University of New Mexico.
Transits of Venus occur in pairs separated by about 8 years, once every 113 years or so. At least, that’s what I gathered from the information about the last two pairs, in 1761-69 and 1874-82. That’s why this is being described as “last in our lifetime”: only someone born very recently, say five years ago, has any decent chance of living to see the first transit of the next pair.
At any rate, if I have time, I may add another image later. I just wanted to preserve these images for my own perusal.
UPDATE As promised, here is an image from Norway as the transit was just about complete: