Daytona as the last race of the season

"Rubbing isn't really allowed."
That's funny, I can tell you obviously haven't watched many NASCAR Nextel Cup races. Rubbing is a regular and frequent occurence on the track at a NASCAR race - although the sanctioning body has cracked down on frequent offenders in recent years. The problem you might have had is which race you were watching. At a large track like Daytona or Talledega rubbing is rare. It's simply too dangerous at the speeds those long tracks produce. However, NASCAR, runs every kind of track possible (with the exception of a street race - not to be confused with a road course race, a street race is just that - a race run through the streets of a large city). NASCAR runs races on large and small tracks. If you're interested in seeing rubbing, check out a race from Bristol, Martinsville or Richmond. They are all short tracks and less than one mile around. Essentially the cars are all bunched up running together. Faster cars often get stuck behind slower cars and have no choice but to "nudge" or "bump" them out of the way. It is rare that a race at one of these tracks (and there are two at each of those a year) doesn't end with some angry comments and/or pushing and shoving between drivers. Their are two very famous Bristol incidences that stand out as examples of "rubbing." No surprisingly they both involve the late Dale Earnhardt. In 1995 Earnhardt was racing at Bristol. He was near the front of the back, stalking leader Rusty Wallace. Push came to shove and Rusty ended up into the wall and wrecked. This with a car capable of winning. Needless to say, Rusty wasn't happy - despite his friendship with Earnhardt. For his actions Earnhardt was penalized for rough driving and sent to the back of the pack. This, didn't seem to phase him. He spent the rest of the race bashing and smashing his way to front. Finally he found himself in second place behind leader Terry Labonte heading into the final laps. Earnhardt tried everything to get buy and on the last straight away he turned Labonte's car into the wall and wrecked him. However, Earnhardt was too late. As Labonte slammed into the wall he crossed the finish line still in first place and won the race. This created the memorable scene of Labonte pulling his demolished race car into victory lane.
Four years later the scene was reversed. Earnhardt was leading the night race at Bristol in 1999. Labonte was chasing him with fresher tires on his car. Labonte caught Earnhardt and nudged him out of the way taking first place. Everybody assumed Labonte with fresher tires would pull away, but the determined Earnhardt wouldn't see to it. With old tires, he caught Labonte and tried to get past for a couple laps. This time Earnhardt acted faster and in the final corner he spun Labonte out of the way. Earnhardt dove underneath Labonte's spinning race car and crossed the finish line the winner. He was not punished or sanctioned by NASCAR in any way (why would he be? The spin out made virtually every sports highlight show in North America - even in areas where NASCAR isn't popular). This was actually one of the final wins of Earnhardt's career. It produced the classic victory lane celebration where Earnhardt, clearly sheepish about what he did, exited his car to a chorus of boos from the in excess of 130,000 people at the race, and exclaimed that he wasn't trying to wreck Labonte, but that he just intended to "rattle his cage a little." It was one of the defining images of Earnhardt's career - as his nick name was the Intimidator.
The point is that rubbing is still very much a part of NASCAR, depending on what race you're watching.
As for your questions about Daytona - the Nextel Cup series (formerly Winston Cup, if you're wondering about the name change) runs two events at Daytona each year. The Daytona 500 - the season's first, biggest and most lucrative race. Then in the middle of the season the series returns to Daytona on the July 4 weekend and runs a 400 mile event at night and under the lights.