The red and green color combination is used almost exclusively for Christmas. Which is too bad, as it can look really spectacular for the rest of the year, too:
The complimentary colors are bold and brilliant, which makes them perfect candidates for grouping with white and natural materials, as seen in Kathryn Ireland's Ojai home from House Beautiful. We love this home office and reading nook that pairs red and green perfectly without it feeling at all too Christmas-y. Rather, the pairing looks perky and fresh.
Image: House Beautiful

White Enamel Four-P...
I love this color combination ~ so cheerful!
Agreed, it doesn't look Christmasy if you avoid kellyish greens and instead use yellowish greens and/or bluish greens.
That looks surprisingly awesome!
I love this color combination. My living room is done in reds and greens. I agree with Miami's Elaine about avoiding kellyish greens.
Red + green (and pink + green) are some of my favorite colors together. The Rhyme comes to my mind however that 'Red and green should never be seen, unless on an Irish Gypsy Queen..' I think the room pic on the right could very nicely be for a gypsy queen.
Bed is currently made in red and white stripped duvet and shams accented with lime green and white stripped bolster pillows. Feels fresh and fun, not christmas-like at all.
I think what makes this combo work, and seem less Christmasy, is LOTS of white. Fabrics with red and green work best with lots of black -- very folk art. Another way to neutralize the holiday feeling is to add smaller amounts of lots of other colors, so the effect is more "rose garden" -- it feels more like Christmas when it's just red and green, especially if you add metallic gold...
Off-hue versions of the colors like fuschia or magenta or lime green also weaken that holiday sensation.
I'm a little red and greened out. My mom's entire house has been these two colors almost exclusively since I was a kid. But she's always added other seasonal touches: flower paintings and drawings, a leaf motif. These really bring it out of the Christmas realm.
She's also pretty good about bringing in enough yellows and orange to keep it from going too far.
It makes me surprised when I hear people say the combo is too Christmas-y.
Wow, a slideshow format that is even more annoying than AT's!
I LOVE her house. And how lucky are people in California who can have carpets outside?