You can go back to college.
My first graduate class was a 6-week, like-drinking-from-a-fire-hose general exercise physiology class last summer. Because that material forms the basis for every single discussion that comes after, I felt the need to be exposed to it again (and again and again...since that's how you learn something to a professional level). My then-advisor was teaching the full-semester version in the fall so I sat in on the class. I attended, took notes to ensure my attention, and then left the classroom and didn't worry about it until the next class meeting. Because I was never lost or behind and I am very pro-learning, of course I enjoyed the experience.
I enjoyed it so much that I decided to do it again. But in a completely different subject. That has nothing to do with either of my Masters degrees. And thus began what I am calling my "enrichment class curriculum". Or "bilking Indiana University out of $4k per semester."
This semester I am sitting in on M212, which translates to second-semester single variable calculus, because calculus is easily my favorite academic subject. ("Hi, have we met? My name is Kelzie and I'm an unapologetic nerd.") I took this class for academic credit my senior year of high school and then moved onto multi-variable calculus etc etc in college.
This class is like conducting an academic archeological dig in my mind. Some topics the professor introduces and I'm like "uh, yeah, I never learned that" while other topics look familiar and come back as soon as the surrounding rock is scratched away, but the weirdest part is when I just see a problem laid out in front of me, knowing exactly how and what to do, despite not having done it for 15+ years. It must be what it's like to crack open a boulder and find a fully intact skeleton right along the fault line. The skills are just...there. The other skills will only eventually reveal a complete skeleton after being (re)excavated grain of sand by grain of sand with a paintbrush.
I'm already drawing up a plan of study for my "enrichment" degree. Choosing potential classes is a delicate balance of large class sizes so I can easily hide in the back - many topically
fascinating courses are too small in which to hide - and knowing something about the topic, but not too much - so that I won't get behind when I don't do the homework, but won't get bored either. Sadly, as much as an intro philosophy course interests me, I don't have time to do hours of reading just can I fully understand lectures in a class that I'm not officially taking. There are limits to my nerdiness - even if I am only finding them now.