Have you ever been online and seen a few (or more) VATSIMxxx callsigns flying around (e.g. VATSIM5, VATSIM6, VATSIM10)? Have you ever been online controlling and had them fly in? I remember when I was a relatively new S3 and had a string of low number VATSIMs fly in while I was controlling, thinking "Oh boy, here are some of the founders, I'd better not screw this up!" And I remember getting such great feedback and big thank yous from them after landing.
A couple of weeks ago, I was departing an airport when VATSIM10 was coming in. He popped onto Center's frequency, made his position report, and got a descent clearance. It was one of those days (which is most every day ) when I was particularly appreciative for VATSIM, all it's taught me, and all I've been able to give back. On frequency, I shot out a quick, "Hey, thank you for VATSIM!" Perhaps a tiny bit startled, but certainly kind and gracious, the pilot, Mike Hayden, CID 800010, one of the founders of VATSIM, shot back a quick laugh and said, "Hey, you're welcome!" I wonder how many times, especially these days, over 10 years later, Mike or the other founders get thanked. We ended up chatting later that afternoon on the phone for nearly an hour -- an absolutely wonderful conversation where I got to thank him (and ask him to pass it on to the other founders as well), and where he thanked all of us for keeping VATSIM alive, growing and vibrant.
Mike mentioned that he and a couple of other founders and a couple of their good friends do a USA fall flying season every year, where they do a bunch of flights into, out of, and all around the US. I mentioned that I had noticed it, and had several conversations with lots of our controllers across the US about how neat it was to be able to be on for the founders (et al). I offered that when they knew their itinerary, to feel free to let me know and I'd post it to see if we could get positions staffed for them a bit more than just the normal "I controlled a founder by accident today". I don't want to take anything away from that experience ("Cool, I worked a few founders in/out today!"), but Mike sent me their plans for their first couple of flights for the season, and I figured I'd post them in case people want to staff up for the founders, et. al. It's not like a big VA fly in/out event, so I'm not going to ASK that these are staffed up, but it is a nice opportunity.
Feel free to let others in your ARTCC know, especially for those that might not come onto the VATUSA forums all that regularly.
And, don't be afraid to say, "Thanks for VATSIM!" I know they'll really appreciate it.