After long, fruitless years of studying, I have finally done it: I have found a legitimate use for stop signs!
They are good screens for projecting annular solar eclipses on.
I was happy to be along the path of this evening's eclipse and by using a mirror I was able to watch the reflection of the whole thing (until the sun set). Awesome!
I also used a pinhole and reflections in car windows and another group of eclipse watchers let me look through their welding helmet as well. And I did sneak some peeks as the sun set and was dimmed by haze.
Here's a regular picture of the annular eclipse taken by my mom during the maximum.