Venus is currently passing right between us here on earth and the sun. This is a rare effect and will not occur again until 2012 then approximatly 100 years after. It last happened in 1882.
Nasa has put up a page here about it:
http://sunearth.gsfc.nasa.gov/sunearthday/2004/index_vthome.htm
There are also numerous live webcasts and streams to watch this event..
I think its pretty cool
