I highly recommend nand2tetris to everyone. For me, nothing ever explained the whole domain from logic gates and inner workings of a CPU to compilers better than this course.

I think it's worth mentioning Gustavo Pezzi's lectures at pikuma.com. The one on "Digital Electronics" and the one on "Interpreters & Compilers" really helped me.

On a side note, why is imrozim's comment dead? What in the world is wrong with it? It's perfectly fine IMO.