Started by Australian GT regular Trent Harrison, the 'Just Send It' comp on iRacing was meant to be a bit of Tuesday night fun for a group of mates.
However it's grown into something much bigger, with capacity grids of gamers lining up against the likes of Shane van Gisbergen, Scott McLaughlin, Anton De Pasquale, and – every now and then – Max Verstappen and Lando Norris.
"I thought I'd just have a crack at it," says Harrison about forming the league.
"It was 3pm on a Tuesday eight weeks ago. The race was full, 45 people in Mercedes at Spa. [Lando] Norris, [Max] Verstappen, van Gisbergen, everyone was on there. I was thinking 'oh my god, what have I done'.
"I was nervous setting the session up, because Shane sent me a message saying Norris and Verstappen were on."
The races, now run at 7:30pm AEST every Tuesday, are live streamed and place-getters are awarded modest prize money on a weekly basis.
"It's gone crazy, I can't believe it," adds Harrison.
"I'm not surprised that fans and the general public want to get involved. That's their heroes that they're racing against. Most of the time they just watch them on the TV.
"For the professional drivers, they like the fun side of it. It's a bit of a release for them, I suppose. They're not pressured to go and win, they're not pressured to do anything silly."
The exact line-up of real-life professionals on any given week is determined by their real-life schedule.
"There is always someone there, always a few of these [professional drivers," says Harrison.
"But the guys are away a lot as well. Scotty Mac seems to always be around, he's focussed on his Supercars stuff. But van Gisbergen wants to drift everything and race everything, so he's away a bit.
"We've got a lot of pro sim racers on there as well. Josh Rogers is the current World Champion, and he's on there almost every week.
"He beats everyone easily. McLaughlin hates that he's so good. He says 'I swear to god that bloke cheats, he's two seconds down the road'. And we're all like 'well now you know how it feels Scott. It's called karma, my friend'."
According to Harrison, there are no passwords or iRating requirements.
Entry is determined on a first come, first served basis (even for the pros), and driving standards are limited to a strict ban on intentionally wrecking another competitor.
"It's pretty casual. Anyone with an iRacing account can do it," he says.
"There are a couple of rules; if you're a tool, and you intentionally destroy someone's race, you'll get disqualified. It's pretty simple.
"We've spoken to the broadcasters and said you must have a beer in hand when you're commentating.
"It's about fun, we don't want to be interviewing the Supercars guys. They've got have fun too. It's got to be light-hearted.
"The other rule is that you've got to have your microphone on. So there's in-game radio chatter that you don't see on the broadcast.
"Everyone can talk to Shane or Scott or whoever is online. Banter is encouraged.
"But it's not serious. If it gets serious, I can promise you those guys won't come back."