The first reality show Concord native Rachel Reilly went on saw her cooped up in a house for 41 days during the summer of 2010.

Last July, she returned to the same house for another season of CBS's summer guilty pleasure, "Big Brother," eventually enduring 75 days, outlasting 13 other competitors and walking out of the front door a half-million dollars richer.

So Reilly, 27, has won a televised competition on a small playing field. Beginning at 8 tonight (again on CBS) she'll try to claim a victory on a much, much, much larger one.

She and her fiance, Brendon Villegas (they met on "Big Brother"), are among 11 two-person teams that will trot the globe on the 20th season of the Emmy Award-winning "The Amazing Race."

Over three-plus weeks last fall, the production visited 22 cities across five continents and covered nearly 40,000 miles, with contestants competing in challenges ranging from skydiving in Argentina to training with Masai warriors in Tanzania.

"It's like comparing apples and oranges," says Reilly about the differences between "Big Brother" and "Amazing Race." "The race is so much more fast-paced - instead of being secluded and cut off from everything in the world ... you're in the middle of the world. You're in the middle of a crowd of people at all times."

On "The Amazing Race," teams travel by plane, train, automobile and other modes of transportation as they race to solve clues; last team to each of the "pit stops" is eliminated. On "Big Brother," players are "evicted" from the house one by one by their peers, and then the winner ultimately is selected by a jury of those peers.

In both seasons of "Big Brother," her brash personality often grated on her fellow competitors and viewers, although it was clear the second time she had learned how to keep herself in check.

"(The first season) I was definitely more in people's faces," says Reilly, a 2002 graduate of Northwest Cabarrus High School who moved to L.A. after earning a chemistry degree from Western Carolina University in Cullowhee.

"But (the second time) I think that I definitely learned how to play the game a little bit better. You have to hold your tongue a lot, and I learned that. I think a lot of the fans really turned over to my side, too, because of that - because they could see that I was really developing as a person and also as a game player."

As for how she comes off on "Amazing Race"? "You'll have to watch to find out."