@daremo This will be pretty random, but maybe you'll find interesting things. I'm leaving out the obvious historical things that we've all heard of. Some of these links may be more interesting for their references.
Forth and Stack machines:
Interesting extreme parallel architectures:
(Not extreme, but parallel in the small that I think is overlooked.)
EDGE from MS research:
Papers from Conway and Patterson:
If you like homebrew CPU architectures, or just CPU architectures in general, you might like the anycpu forum...
(There are a few sub-forums - a few too many perhaps - I always use New Posts as my landing page, but you need to be logged in for that. It's pretty low traffic.)
"I appreciate SDF but it's a general-purpose server and the name doesn't make it obvious that it's about art." - Eugen Rochko