Since NASCAR's early days, stars of open-wheel racing have occasionally stopped by to visit.
Things have changed. Now they're coming to stay.
The 2008 Daytona 500 will have at least three Indy 500 winners on the starting grid -- Juan Pablo Montoya, Sam Hornish Jr. and Dario Franchitti. Jacques Villeneuve will make it a historic foursome if he qualifies.
Having Indy 500 winners at Daytona is nothing new. Even 45 years ago, four men who would win Indy competed in the Daytona 500 -- A.J. Foyt, Johnny Rutherford, Troy Ruttman and Parnelli Jones. But two of them -- Jones and Rutherford -- hadn't accomplished the feat at the time.
The 1981 race was the last time two men with Indy 500 wins on their résumés -- Rutherford and Foyt -- competed in the Daytona 500.
In the past, the big names of Indy were just passing through, racing in NASCAR's biggest show as a little sidelight before heading back to the open cockpit.
And for the most part, they were Americans who sounded the same (well, sort of) and didn't have hard-to-pronounce names. They just happened to spend most of their racing careers in a different discipline.
They could make more money and gain more fame by concentrating on Indy cars. Frankly, the idea of racing full time in NASCAR was laughable.
Who's laughing now? Indy-car racing did everything possible to destroy itself over the past decade with two competing leagues and constant feuding.
The open-wheelers are here now because it's the place to be. The men who won the past two Indy 500s -- Hornish and Franchitti -- will race full time in Sprint Cup. Neither will race in the 2008 Indy 500.
Montoya coming to Sprint Cup last year was just the beginning. Montoya is a Formula One winner, but Villeneuve is a Formula One champion (1997). Villeneuve and Patrick Carpentier are Canadians who plan to race full time in Cup this season.
Cup will have four foreign-born drivers competing for the first time. Montoya is Colombian and Franchitti is a Scotsman.
They are bringing attention to the sport from people and places that never cared in the past. But there's also an element of NASCAR's old guard that doesn't like it.
No one is screaming, "Go back where you came from." At least not publicly. But some NASCAR traditionalists feel the open-wheelers are taking rides away from young short-trackers trying to move up.
NASCAR officials have embraced a "return-to-its-roots" theme for the 2008 season to try to regain the trust of the old-school fans. Obviously, the open-wheel invasion doesn't help sell that concept.
Most of the veteran drivers don't care. The open-wheelers are just other guys they have to beat.
"To me, it makes no difference," said Ryan Newman, Hornish's teammate at Penske Racing. "I was an open-wheel driver [sprint cars] when I came in. I just wasn't an IndyCar driver.
"The bottom line is they're drivers, they're competitors. I don't care whether they're male or female, open-wheel drivers or late-model drivers from the local short track. They will learn if they deserve to be here. In the car owners' and sponsors' eyes, they feel that they are."
Clearly, these are accomplished race car drivers with unquestioned talent. But learning this style of racing and becoming successful at the Cup level is no easy task.
The days of showing up every now and then and winning the Daytona 500, as Foyt and Mario Andretti did decades ago, are long gone.
This is an uphill climb on an icy slope. It's unlikely any of them will enjoy the type of success Montoya had last year when he finished 20th in the standings. Montoya won the road race at Sonoma and had six top-10s.
For now, Montoya is in a league of his own among the open-wheel newbies.
"I'm so proud of what Juan did last year," said team owner Chip Ganassi. "What makes me even more excited is that I know he has only scratched the surface of what he is going to do in a stock car. He is a talent like few others."
Talent isn't always enough. Carpentier and Villeneuve don't have guaranteed spots in the field, racing in cars that never have come close to winning.
Hornish, a three-time IndyCar Series champion, does have a guaranteed spot. He swapped points with teammate Kurt Busch. But Hornish is part of a new third car at Penske with a new crew, an almost certain recipe for struggle.
Franchitti is going to an organization (Ganassi Racing) that hasn't won an oval-track race in five seasons.
It makes you wonder why any of them want to do it.
"It was a tough decision to make," Hornish said. "But I got to a point in my career where I decided this was the next challenge.
"I felt that I was at the right age  where I could do it, where I didn't feel like I'm too old or too young. I accomplished more than I ever thought I would in an Indy car, but I wanted to know I could do this, too."
All of them say they welcome the challenge. No doubt that's true, but there are reasons none of them talk about.
Money tops the list. NASCAR is their best option for cashing in while they can. Villeneuve and Carpentier are 36. Franchitti is 34. Time is running out.
Another reason is safety. NASCAR has become a much safer form of racing compared to open-wheel cars. Franchitti was lucky to escape unhurt from two terrifying airborne crashes last year en route to the IndyCar Series championship.
Whatever the reasons, all of them are risking their reputations to show they have the skills to make this work.
"I know it's going to be hard," Franchitti said. "But every year since I started racing, I've always asked myself one question at the end of the season: 'Do I still want to do this?' Being in NASCAR is what I really want to do."
Terry Blount covers motorsports for ESPN.com. He can be reached at email@example.com.