In June of 2002, I was living in a garden-level apartment over on Lincoln, and working part-time at Treads in Englewood. The shop was only about a mile and a half from where I lived, so I usually rode the bike down there, after getting off work at federal Highways.
On the 8th of that month, I drove home, changed clothes, and jumped on my KHS fixed gear to ride to the shop. As I rode along, I noticed a weird quality to the light, which I had not noticed through the windshield of the truck. I looked up, and saw the sun in the sky. Oddly, though, I could stare right at the sun without any discomfort.
By the time I got close to the shop, ash was filtering down out of the sky. Nuclear winter?
No, it was a forest fire: The Hayman Fire ended up being the largest fire in the recorded history of Colorado. It burned until almost the end of July, and limited our Front Range mountain biking for quite a while.
Funny how I didn't even notice anything wrong from inside the truck, but I was attuned enough to my surroundings, on the bike, to see it...