Americans! Take note.
When you do not care one way or the other, the phrase you are searching for is, "I couldn't care less about..." Let's use a worked example. You're not fond of ice-cream and you don't want to go to your friend's house. Your friend says that if you come over to her house, you can have ice-cream. Your reply should be, "I couldn't care less about ice-cream." In this instance, as in every instance, "couldn't" is a contraction of "could not". This means - roughly translated - "I could not care less about ice-cream." It is physically impossible to care less about ice-cream. You don't care at all.
Americans, you always seem to say, "I could care less about ice-cream". Whilst this may be symbolic of an over-fed, over-sugared nation, if you genuinely care not for our creamy, icy friend, you are unfortunately substanially grammatically weak. Your phrase, "I could care less about ice-cream" means, "I do care about ice-cream enough to be able to care less about it. Ergo, it is possible for me to care less about ice-cream, therefore I don't dislike ice-cream all that much."
This makes no sense. Go away and think about what you've done. And next time, don't be so rude to your friend who was inviting you over. She might have had chocolate too.