There was an "official" C compiler for NOS running on the CDC Cyber. As I recall, 18-bit address, 60-bit words, more than one definition of a 'char' (12-bit or 5-bit, I think). It was interesting. There were a lot of strange architectures with a C compiler.

I would also point out architectures like the 8051 and 8086 made (make...they are still around) pointer arithmetic interesting.