Geology geeks, take note: the USGS/Cascade Volcano Observatory website has some fascinating still and moving images of the Mount St. Helens lava dome growing over the past couple of months.
Recently, the USGS began publishing short AVI movies of the dome's progress, as seen from a camera *inside* (!) the crater. The August 16 movie is comprised of 45 stills over a 60-day period, and depicts dramatic changes as one portion of the dome rises and collapses — not unlike a gloppy pot of oatmeal on your stove: [small, 1MB; large, 2.8MB]
The site also offers medium and high-resolution still photos, updated daily, which make nifty, nerdy desktop wallpaper.
(Thanks, Mark!)