Singularity Day

Which day will historians pick say, 100 years after the event?
I judge the singularity to arise at the bottom of a major depression, say the pit of a second dip. These rare gems come about once per century. We got one. This dip should be a singularity day.
We will get patrol bot, a small model electric car that roams the neighborhood quietly watching for the nefarious. Deliver bot at $1/(cubic-foot * mile). Delivery cost to the curb, $1 for pizza. Bots on the road, the story of the next century.