NASCAR had a little more shady beginning, as moonshine runners in the southern U.S. were constantly looking for ever-more souped-up engines and auto bodies that could outrun the latest police vehicles. These bootleggers began racing one another for sport and testing of their vehicles, and eventually NASCAR was organized as a national body to set rules for such competitions. As the races moved from booze-running to more "socially acceptable" events, auto manufacturers were happy to enter their cars in the races to prove themselves and get publicity. Originally, NASCAR used stock cars -- cars that could be bought and driven on the street. It wasn't uncommon for a racer to drive his car to the track, race, and then drive it back home. (Unless, of course, he had a bad day and the car ended up leaving with some assistance from a wrecker truck.)
Nowadays, the cars used in NASCAR aren't street-legal, so it's not really right to call them "stock cars" anymore. Somewhere along to line as well, the focus went from the car to the driver, and made cult heroes out of the drivers themselves. NASCAR, wanting to compete with "legitimate" sports like football, baseball, etc., began to market itself to a wider audience than just the automotive enthusiasts who used to watch. They branched out from their southern U.S. roots and held races in all parts of the country, even abandoning some of their traditional venues. Drivers were marketed to the saturation point with t-shirts, jackets, caps, bumper stickers, and just about any kind of cheap plastic gizmo you could find. (Some of my in-laws' friends got me a NASCAR coffee-maker -- yes, coffee-maker! -- for a Christmas gift a few years back. I'm waiting for a white-elephant gift exchange to dump this to....

My dad is an automobile lover, and he and my mother used to watch races, both Indy car and stock car, on TV, but in later years, they complained about how it was getting too commercialized and like every other sport (my parents are/were not big sports fans in general), and they lost a great deal of interest in it.
So when we ask if it's really a sports, yeah, unfortunately, NASCAR is fast turning into just another mindless sport.
