One more - KEO
This satellite will remain in Earth orbit for 50,000 years and then return,
carrying lots of information and messages for who or whatever is on
our planet by then:
http://www.keo.org/
The storage capacity of KEO allows every person on Earth to send the
equivalent of a 4-page letter to the future. The deadline is December 31, 2008, so hurry!
http://en.wikipedia.org/wiki/KEO
