Since 2005, IZOD IndyCar Series drivers have navigated the challenges of road and street circuits mixed with ovals of all sorts in pursuit of the most demanding championship in motorsports and its $1 million bonus.

Dan Wheldon, Sam Hornish Jr., Scott Dixon and Dario Franchitti have prevailed -- with each of the title duels culminating in the season finale. There are equal parts ovals and road/street circuits embedded in the 18-race schedule (17 events, including the Firestone Twin 275s at Texas Motor Speedway), with the finale scheduled for Oct. 16 on the Las Vegas Motor Speedway oval.

That should be plenty of time for five potential challengers to sharpen their oval racing skills to collect on a cool $5 million payday courtesy of the sanctioning body. The catch? Win the race.

INDYCAR CEO Randy Bernard dovetailed the challenge with the IZOD INDYCAR World Championships announcement at the chic Crystals CityCenter on the Las Vegas Strip. Tickets go on sale Feb. 25 at Ticketmaster.com.

“We showcase our drivers as being the very best, fastest and most versatile in the world,” he said, “and we are putting our money where our mouth is. If any race car driver in the world outside of the IZOD IndyCar Series can win the Vegas race, we will give you $5 million. We will accept five entries for this challenge, with entrants being determined by a selection committee by mid-summer.

"There are a lot of drivers that talk about wanting to race in INDYCAR. We believe that the skill set it takes and just the toughness and willpower to get behind the wheel of these cars is pretty amazing.

"Those top drivers are going to expect to have a great team, so they are going to have to talk to the Roger Penskes and the Chip Ganassis and the Michael Andrettis and on down and make sure that they feel that they have a shot of winning this race."

Sounds enticing; enough even to get Al Unser Jr. and KV Racing Technology-Lotus co-owner Jimmy Vasser to contemplate coming out of retirement for the date.

"I tell you, $5 million would sure make you think about it," said Unser, a two-time Indianapolis 500 champion who is a driver coach with INDYCAR. "I'd lose 10 pounds and I'd call Roger (Penske) and try to make a deal with him. It would be like old times. It's Randy taking the lead with the IZOD IndyCar Series and it's going to be great."  

BTW: The NASCAR Srint Cup Series competes at Charlotte Motor Speedway the night before the IZOD IndyCar Series race.

INDYCAR christened the $72 million Speedway Motorsports Inc.-owned superspeedway in September 1996, with Richie Hearn taking the checkered flag. Eliseo Salazar, Arie Luyendyk, Sam Schmidt and Unser also won INDYCAR-sanctioned races through 2000. Sebastien Bourdais won Champ Car races in 2004 and '05.

The 1.5-mile racetrack was reconfigured in 2006, with variable banking (to 20 degrees) one of the more notable projects. Unser said the racing was exciting a decade ago and expects the higher banking to increase the competition.

"It will definitely race a lot like Chicagoland (Speedway)," he said. "With the added banking you're going to have more grip. When I raced here in 2000 we raced side by side but only two rows could do it. The third row didn't have enough grip to do it so with the added banking you're going to see side-by-side racing six and seven rows deep. It's going to look a like what goes on at Chicagoland and Texas, and we know how exciting those tracks are."

Team Penske's Ryan Briscoe, who tested at the speedway in October, agreed.

"I can tell you it's going to be the closest race we'll have all season, so it's the perfect place to have the world championships," Briscoe said. "It's going to be the fastest track we go to outside of Indianapolis and it's going to be unpredictable. There will be two-and three-wide racing, and even four-wide like we've seen before. If you're a fan of any form of motorsports, this is the race you should come to."