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I recently signed up to the project-blogging community at hackaday.io - the website design leaves something to be desired, but there are quite a few interesting projects (and people) to be found there.

You might be interested to explore, or if you share my interests, to start with a look at the projects on my like list. Pointers to more projects I might like are very welcome!

As a bonus, one of the people there mentioned the TIM8 relay computer, which has an interesting dynamic RAM made as an array of electrolytic caps:

(That's 96 caps and, apparently, twice as many diodes.)

There's also video or two linked on that page.

Among other things, hackaday.io has the idea of collections - curated lists of projects. They are not always frequently updated, but they are good lists anyway. And, for the very determined digger, having a look at the home pages of the people who follow those lists might well show up more good projects and people.

Here are some examples:
Homebrew Computers 4 bit, 8 bit, tiny, micro, diy laptops, rebuilds, restorations & computers in a can

Hackaday TTLers Where DIY DIP/SSI/MSI CPU makers meet and discuss other TLA (three letters acronyms)

65xx ProjectsProjects using the 6502, 65816, and other related CPUs

Calculator Projects Crunch some numbers with the help of these projects

Retrogaming Hardware Hacks Retrogaming on real hardware! No Emulators needed.

There's a new and growing curated collection on hackaday.io:

Homebrew CPU

with, presently, some 45 homebrew CPU projects, in various technologies: FPGA, 74181s, TTL, transistors, relays.

There are some really nice ones there! I wish I could give them all the time they deserve. I clicked "Follow this list" on it.