This is the site that convinced me to seek out and buy a PDP-8 of my own back in 2008. Not a PiDP-8, a 1971 PDP-8/e with 12KW of core memory, a TU56 DECtape, a VC8E vector boardset, and a couple teletypes. And then a '73 8/m. And a '75 8/f. And many, many boards and gizmos. And and and. It's been a 6-digit...mistake? Investment? Hobby? Labor of love?
They're not particularly powerful computers, particularly in 2023 - basically a microcontroller in today's terms - but man are they visceral.
SIMH does a good job of letting you run PDP-8 software, but if you want to poke around inside a PDP-8 I really recommend Brian Shelburne's PDP8MAIN simulator (for DOS, but runs perfectly in DOSBox). You can get everything you need here: https://github.com/rrutt/PDP8/tree/master
A PDP-8 programmer's reference from 1969 is available here: http://www.bitsavers.org/pdf/dec/pdp8/handbooks/IntroToProgr...
It's a lovely system. Extremely minimal, but capable and entertaining.