It was painted that way in celebration of CO's 75th anniversary back in 2009. A little bit of trivia. It was the first aircraft CO took delivery that did not have the Sky Team logo on it. Continental Retrojet by Olton Hall, on Flickr IMGP6437 by Olton Hall, on Flickr
Keep smiling guys, cuz I'm gonna give you a lot more than smiles in the next 5-7 years, and I think you'll like it. Also, this pic is dying for a Pinky and the Brain reference.