I still blame the sun for the dead pixels on my 7D, it was just after I took photos of the eclipse of 04/01/2011 that I noticed all the dead pixels. Was with my 70-300 non-L and 15-85, at 300mm and 85mm, so both f/5.6 for framing but f/18-22 for the pics, some at f/36, speeds from 1/640s for the wide-shots but 1/2500-6400s for the 300mm shots.
I started off with the viewfinder but gave up after half a second and moved to live-view, I tried to keep my finger on the DOF-preview button but couldn't always. If I had an ND, that would have been when to use it, but I didn't at the time.
It was 2 weeks later doing long-exposures that I noticed the dead spots and put my camera in *3* times for warranty-fix (took them that many times to actually get rid of them all). I've just had another look, and I can even see the dead pixels in high-iso shots I took that night after the ecplise, and I can't see them in night shots taken a week before.
So yeah, I'm not pointing my camera at the sun ever again, without a pinhole or 20+ stop ND. Feel free to do it to your own camera though...