I don't follow it too closely (no cable, so I resort to checking the standings every once in a while), but, when I'm home visiting my parents, I can watch every lap of a NASCAR race with my dad. I grew up in a NASCAR home, and my dad used to be somewhat of a local racing legend when I was growing up, so I'm easily captivated by racing. I'm fairly certain that racing would have zero appeal to me had I not grown up around it. But when you experience enough of it, and get into the mechanics of it all, and factor in the speed/risk factors, it becomes pretty exciting.
Of course, at its most basic explanation, it is 40 or more cars just driving around in circles, but when you use such a short, simple explanation, every competitive sport sounds dumb and boring. Why would I want to watch some guy throw an oddly shaped ball to another guy, and then watch people try to tackle him? Why would I want to watch some guy hit a ball with a metal club, go find it, and then..hit it again..and again? Who could possibly want to watch a team of 8 or 9 guys try to throw a ball through a hoop? Or throw a ball really fast at a guy to see if he can hit it.
When you use such a broad explanation, every sport sounds pointless and boring. I find it extremely challenging to stay awake during a football game. I'd rather watch the paint on the court dry than watch a basketball game. You want boring? Watch sweaty dudes run around for 3 hours straight.
And say what you want about race fans and drivers alike. There's a lot of skill and knowledge that goes into tuning a car to get the absolute most speed out of it. That's what draws me into it the most is the technical aspect. Spend some time in the pits of a local track and just observe how much work goes into a car on race night. Broke something in practice, or your heat race? You have about two hours tops to get it repaired, tuned up, dialed in, and just right. The track's cooler now than it was earlier today? Time to start adjusting your tire pressure, or maybe swap out the right front spring for a fatter one. Lots of dust in the air today? Time to swap out the radiator that has larger gaps between the fins, otherwise it's going to get clogged with dust, and you're going to lose some serious horsepower.
I can see how people find NASCAR to be boring though. There's a lot of restrictions, and the cars are largely the same, but still, there are different engine builders, every car setup is different, and there's actually a lot of skill and strategy involved. If you want to see some real good racing, go to a local track. Smell the high-octane race fuel, listen to the engines, and watch the cars rubbing and bumping all over every inch of the track. Then mix in the egos, rivalries, and attitudes, and you've got yourself an awesome night at the track.
That's my pro-racing rant.
Edit: My father and I went to the Sylvannia 300 in Loudon, NH a couple weekends ago, and it was a blast. We had awesome (free) seats, and spent the day sipping $4 beers and watching the race. I'll remember that day forever.