I've never been on either end (no homo) of a formal mentorship. However, I've had someone whom I considered a mentor twice. One was when I was just out of my teens, and he was about 15 years older than me. He was my first role model that wasn't a blue collar union worker. I have actually surpassed him, in professional terms, but I owe him that first glimpse outside of my circle of association from what I was born into. We are still great friends, some 20 years later, and when I return to my home area, always spend part of my visit with his family.
I also had someone, about a decade ago, that launched me on my current particular career trajectory. I did an internship under her, to obtain some professional licensing. We're still great friends (we did happy "hour" with spouses a few weeks ago and doing dinner Sunday) and again, I have surpassed her professionally. But I still use her as a sounding board, etc. The only difference is, she now using me as a sounding board, etc., too.
I took on an intern a few years ago, and found the process extremely enjoyable. I'm assuming he did too, as my bottle of Louis XIII was a gift from him

He contacts me about once a quarter, but has moved far away in pursuit of his career.