Some of these are a bit old, but well worth seeing:
- Thierry Legault's remarkable images of the Space Shuttle Atlantis and ISS transiting the sun. (Be sure to spend some time on the rest of the site. Those aren't the only amazing images there.)
- The volcanic eruption of Sarychev Peak as seen from ISS, in 3-D (get your red/blue glasses out), and as an animated clip.