For the entrepreneurs among us, the business story here is that these fantastically detailed sims were expensive to make. The three 20-year-old sims at the github link, Grand Prix Legends (GPL), Mig Alley (MA) and Falcon (FF) were all bet-your-company high concept projects that expected a lot from their customers in 1999.<p>MA did OK in the market but that only encouraged it's creators to make a follow-on product that tanked their company. GPL and FF were commercial flops, and the companies that made them soon disbanded. Nevertheless, GPL and FF evolved into what are currently best-in-class sim products. The high ambitions and technical wizardry of all three sims inspired dedicated community groups that added content to the sims for years following release. The versions of the sims on the github page include these community-generated add-ons.<p>The FF project was a notorious business mess that somehow propelled itself through years of headwinds with a kind of prodigious creativity. Both the mess and the creativity are on display in the 1000 page volunteer-created FF manual on github.