The noise! The dust! The action!
I went to my first stock car races a few months ago. It was quite fascinating.
There is special red clay soil laid down on the track - I assume so as to give just the right amount of traction on the corners. When the water trucks haven't been by for a while, the clay turns to dust and the haze drifts over the scene. The intermediate stage is when great clods of it are flung out of the track area by the cars, landing all over you if you're naive enough to have chosen a seat in the first 5 rows, or are returning with hot chips.
All the cars have very odd shapes, with great spoilers and advertising paint jobs, and they slide almost sideways around the corners. There are frequent stops - they have to look out for the red light, and all must stop almost exactly where they were when it came on - even to the point of backing up. The man comes around on his quad-bike to tell them to back up if they don't. The stops are due to cars immobile on the track; mainly those in a position that is going to prove dangerous to other competitors. Most of the cars need to be pushed to start, so if they spin out or crash, that's often the end of the race for them.
The evening I went, the stands were crowded and the atmosphere was wonderful, especially when the sun went down and the flood lights came on.
Most of the crowd was there for the final event - the demolition derby - old caravans and wooden boats being towed at crazy speeds and bashed and bumped with uninhibited abandon. Steam pours from damaged radiators and the crowd cheers wildly. Last one still moving wins.