Ask HN: Best ways to continue a Computer Science education after graduation?

I'm a recent CS graduate (undergrad) and I'm working full time. I like my job a lot, but there are a lot of subjects that I don't encounter at my job, like complex data structures, compiler development, and other topics that are discusses heavily in college, but not used in most careers.

I don't plan on going back to school, and I enjoy my job, but what are some good ways to be both exposed to new ideas, as well as dive deeper into them? Learning is something that I really enjoy and makes me feel rewarded, but it's not as straight forward now as it was when I was in school.

Optimally, I'd have a reference for the information, and then work on projects to solidify the knowledge. I don't mind paying a bit, especially for a good book.