Cheat answer: LARPing, but a LARP is just another form of RPG.
Cheesy answer: the relationships I’ve made, people I’ve met. My entire network of friends over the last decade has come about because of gaming. Between the people who I met directly by gaming with them to the people who I met by partying with those people, I’ve made a vast network of friends across the world through roleplaying.
When I was in the Imperial Order (way way way back in the day), I could honestly say I was talking to people on five continents on a regular basis – the only ones I didn’t have covered were South America and Antarctica. Nowadays I’m getting name-checked with seemingly every second introduction at events (“oh, you’re the No Rest for the Wicked guy, right?”). It’s an odd feeling but it promotes the community feeling of the LARP crowd (as does small-world LARP syndrome where it seems that everyone knows everyone after a few years and you get the constant “how do you know X?” questions on Facebook).