A site that lets you see in real time radar aircraft traffic movements in the SF Bay Area.
Way back at the start of the computer revolution, I had a "video" game on my Z-80 based computer: it was about air traffic control. Targets arrived, had to be turned and so forth, and had to leave the "control area" at certain points and altitudes.
I killed a lot of electrons, and gained a new respect for air traffic controllers.
W1AC