The Daytona 500 in 1979. On the last lap Cale Yarborough and Donnie Allison collided and then got into a fight, with Donnie's brother Bobby quickly jumping in. It was the first NASCAR race to be broadcast live with flag to flag coverage.
The 1976 500 with a very similar situation, except that no other drivers come past to pick up the win. Two of the sports legendary drivers (Petty and Pearson) inadvertently wreck each other coming out of the last turn and both end up in the infield grass before the start line. Petty oh-so-nearly makes it across the line but slides to a halt, engine stalled. In a CMOA for Pearson he has the presence of mind to press in his clutch pedal while spinning around at about 120+ mph so he doesn't kill the engine, trundles across the line and takes a wrecked car to victory lane.
The 2010 Aaron's 499 at Talladega counts as this. It shattered previous NASCAR racing records thanks to a rules package that gave a record 29 different leaders and 88 lead changes. It was also Kevin Harvick's first win since the 2007 Daytona 500. Not to mention that like that 500, Harvick won in a photo finish drag race to the finish line (this time, outracing Jamie McMurray by mere inches; in the Daytona 500, it had been Mark Martin).
The 2011 running managed to top this, by reaching the same number of lead changes, but within regulation (the previous race ran over by 12 laps due to three green-white-checkered attempts). And this time, the top eight were four-wide at the start finish line, with Jimmie Johnson having gone from fifth to first in the space between turn four and the start-finish line, with a drafting push from Dale Earnhardt, Jr. allowing Jimmie to beat Clint Bowyer by a record-tying 2/1000ths (0.002) of a second.
The 2011 Daytona 500: in his second Sprint Cup startnote tying a modern era record first set by Jamie McMurray in October 2002 at Charlotte and only racing a partial schedule to focus on NASCAR's second-tier Nationwide Series, 20-years-and-one-day-old Trevor Bayne (whose best Nationwide Series finish prior was only third) wins the "Super Bowl of NASCAR" for his first career Cup victory. In doing so, he demolished Jeff Gordon's record as the youngest Daytona 500 winner (by five years) and brought the famed Wood Brothers #21 (with the throwback paint scheme) back into the winner's circle for the first time since Elliott Sadler drove the car to victory lane in 2001. A reminder that this is the biggest event in stock car racing.
The season's end: Tony Stewart went from being winless in the first 26 races and barely making the Chase, then winning four of the first nine Chase races. His slight inconsistency was enough for Carl Edwards (who finished no worse than 11th in those latter nine races) to take a three point lead into Homestead. With Edwards on the pole and dominating early, Stewart roared from the back of the lead lap twice due to grill damage. Stewart won the race, Edwards led the most laps and finished second, and they were tied for the point lead, but Stewart claimed the championship on a 5 to 1 race wins tiebreaker—the first time a Sprint Cup season ended with a tie at the top of the standings. AJ Foyt (whose number Stewart's carried since he owned his own car) later called it Stewart's greatest drive.
Speaking of Crowning Moment of Awesome at a Daytona 500, how about in 1994 when Sterling Marlin, making his first start with a new ownership team, gambled on fuel mileage and won his first Daytona 500 and also his first race in 279 starts, holding off a fueled up Ernie Irvan. Marlin had come close to victory many times, including in the 500 in 1991, but had never gotten over the second place finish hump. Made all the sweeter when EVERY PIT CREW came to high-five him as he drove to victory lane and the very same driver he held off, Irvan, had been the one to beat him in the 1991 500.
They did the same greeting to Dale Earnhardt after he won the 1998 Daytona 500 in his 20th try.
And for another Earnhardt Jr. example at Daytona, the 2014 Daytona 500. A rain delay forced the last 400 miles to be run under darkness, and fans were treated to an ultra-competitive race, with many drivers able to power their way past others. While Earnhardt did lead the most laps, he hadn't done much until the last third of the race, but he could shuffle his way to the front and defend his position as well as anyone, holding off just about every charge thrown at him from the cream of the crop: Carl Edwards? Check. Jimmie Johnson? Check. Jeff Gordon? Check. Brad Keselowski? Check. Denny Hamlin, going for the Speedweeks sweep (winning the Sprint Unlimited, his Budweiser Duel race, and the 500) and trying to steal the show on the last lap? Check and mate. Earnhardt's second 500 was in the books.
Road racing in general has delivered awesome race after awesome race in recent years. The two annual road course races were generally considered yawnfests by most of the NASCAR fanbase, with few drivers excelling in them and the tendency to bring in road racers to fill in. Nowadays, though, they're often considered as entertaining as short track races, and considering that short track racing is the most beloved part of the NASCAR circuit, that's a hell of a compliment. That there have been nine different winners at the last nine Sonoma races, including surprise wins by Juan Pablo Montoya and Martin Truex Jr., has something to do with it; as does the presence of a three year winning streak for foreign drivers at Watkins Glen with Juan Pablo Montoya in 2010 and Marcos Ambrose in 2011 and 2012.