I just finished building a 3TrinsRGB+1c from gieskes.nl. It's an analog video synth/processor with CV inputs. It can also generate it's own sound.
So the build was pretty simple. There wasn't much documentation but a video covers most of process...
and there are some additional details here. The board layout is interesting... and due to the density of parts in some places, there were some resistors I missed on the first pass.
PCB

As you can see, there are SMT parts and some headers which come pre-installed.
Parts

Front panel

Getting started, stuffing resistors

The rest of the passive parts, transistors, sockets, ect...

Getting jacks and pots lined up with the front panel.

Then the rest of the pots, switches and LEDs.

All done.



Here is a pretty poor quality video I did of my first experiment. Audio and CV come from my DIY Eurorack synth.
I will use this thread as a general resource for DIY video synth projects but I also plan to share my own experiences as I go along.