An incredibly bright, polished silver disk, probably about 35 feet in diameter, in broad daylight, about 75 yards away.

I was Crew Boss of a Forest Service Brush Disposal/Fire Suppression Crew.  I was driving  a 3,000 gallon tanker truck up a logging road to a slash burn we were doing that afternoon.  In the vehicle with me was one of my Squad Bosses and the district law enforcement officer.
To our right was a narrow ravine and a descending ridge line about 75 yards away on the other side of the ravine.  I noticed a flash of light out of the corner of my eye to the right and looked over and immediately brought the vehicle to a full stop (we were only traveling at about 15 mph up the logging road.  All three of us looked over to our right and saw a bright, silver disk, a flat rim with a structure on top, resembling a "Skimmer" hat of the 1890s or so.  It was framed against a crystal clear blue sky under an near noonday sun.  It was only traveling at about 5 to 10 mph and was wobbling like it was having some difficulty, slowly moving down the ridge line. we continued to watch it as it moved down the ridge line and then, slowly, dropped down into another ravine on the other side of the ridge line.
None of us said anything for about 30 seconds, we just continued to look over at where it had been, and then I said "Let's not talk about what we just saw, instead, why don't we each just draw a picture of what we saw and get together in a couple of days and compare pictures?" Three days later we got together and we each had, essentially the same image appropriate to each of our skill levels as artists.  We never said anything about it to anyone else.
((
Witness indicates that the date of the sighting is approximate.  PD)