My grad work was in system programming language design; I used to toy around with VM design, so that meant I was (poorly) designing a lot of ISAs and then writing a lot of assemblers for them. My professional work is unrelated to my grad work, but has still let me expand on that interest. Sorry I'm so vague. Think more along the lines of "python byte code assembler", or somesuch thing.
Do you happen to blog? Would absolutely love to read about best practices, curious situations and so on.