Driving my MGB back from the supermarket and heading down the little hill to the beach, I saw a blue MG Midget coming up the hill. We waved at each other. 
67-ish Corvette convertible. Red with a black top which was down. Probably a small block, it didn’t have the big hood scoop.
A classic air-cooled Porsche 911 convertible. I have no idea what year since they had that same basic shape for so long. But I’d guess 1980s or late 1970s.
And once again, I posted too soon. This evening I saw an early 1950s Mercury. It looked mildly customized, but not too much. It appeared to have been lowered a bit, had white-wall tires, and hubs painted red. And dual exhausts, I’m not sure if that would have been offered back then or if that was another modification. Other than that it looked pretty original, with the caveat that I have no idea what was under the hood.
I saw a '60s Corvette convertible yesterday too. Oxidised red, and the top was down. I don’t know what kind of transmission it had, but I could hear grinding as it accelerated away.
Until 1973, Porsche 911s had ‘long hoods’. They had grilles next to the turn indicators. In 1974, they got the ‘short hood’. Safety regulations required beefier bumpers, and the 911 got the bigger front bumper with the rubber strip running along the width, and with a rubber ‘gasket’ (or fairing; whatever) on the top. The rear bumper had large overriders on it. In 1975, the rear bumper overriders got bigger. In 1978, the 911S became the 911SC and it lasted until 1983. (I had a '79.) The 911SC had rear fender flairs. From 1984 to 1989, the 911SC became the Carrera. Porsche used the ‘911’ nomenclature from 1963 to 1989. After that, they used internal numbers (e.g., ‘993’ for the '95 to '98 models), but still badged and marketed them as 911s.
That should give you an idea of 911 years at a glance. Of course there were numerous other changes that can’t be seen (continuously upgraded engines, for example) and smaller cosmetic changes.
A good-condition Pontiac Aztek, Walter White’s car.
I do remember that the one I saw had a “Carrera” badge on the engine cover, so I guess that narrows down the one I saw to 1984-89.
Given my previous pattern, I’ll probably see something more interesting later today, but taking a break from working from home I walked over to the living room and looked out the window, to see an absolutely pristine 1980s era Lincoln Mark VII drive past.
Two things I’ve never seen before, a VW microbus converted into a trailer, very clean and in great shape (pics on imgur, VW bus trailer - Album on Imgur), and a stretch limo … Volvo? (A stretch limo... Volvo? Spotted this afternoon in Redwood City CA. - Album on Imgur)
Gotta figure out how to insert pics here in the post.
A Mercedes AMG S65. It had a very prominent “V12 Biturbo” badge on the fender.
I saw a 1970s Thunderbird, what a hideous beast.
Dad had a 1970 T-bird coupé. I thought it was quite attractive – actually, the last year for attractive T-birds.
VW Scirocco. Perfect condition. Wanted one when i was a teen.
A 7th generation (71-77) Oldsmobile Delta 88 on the highway, doing 80 in the fast lane.
A '75 Ford Pinto wagon in metallic brown, in showroom condition. Definitely don’t see many of those, these days.
3 wheeled car, 2 in front 1 in the back. It has no roof. I think it might be classified as a motorcycle.
Was it a Polaris Slingshot?
I was going to guess it was a Kia Rio, by Japan Japan.
Yes, I know. Go with me, here.
I think it was the slingshot
A Hyundai Venue, never seen one before.