Ask HN: Anyone doing cool stuff with radars?

Recently I got into radars and radar tech from places like:

https://www.wiringview.co/doppler-radar-circuit-diagram/ circuits for basic radars

https://ocw.mit.edu/resources/res-ll-003-build-a-small-radar-system-capable-of-sensing-range-doppler-and-synthetic-aperture-radar-imaging-january-iap-2011/projects/MITRES_LL_003IAP11_proj_in.pdf building a radar with cans(a.k.a. cantennas)

https://training.weather.gov/nwstc/NEXRAD/RADAR/3-1.htm good tips on what to look for when dealing with weather radars

https://www.electronics-notes.com/articles/radio/rf-mixer/double-balanced-mixer.php theory behind common signal mixers used in building radars

and a bunch of others. Is anyone doing something cool with radars ?