I usually fall back on "Oh, wow!" (most people take this as a compliment, even if you're thinking, oh wow, how ugly!!! LOL) And then find something to compliment. You can always find something you like if you look. Even if it's just one of the fabrics in it. Say, Oh, wow, I love that purple fabric in there. Where did you get that? or, How bright and happy looking! or, I've always liked that pattern, or (if all else fails) You must be really proud!! And they probably are!