The answer between saying Yes and No

Yes. There is mostly a way or two when you don't want to answer that troubling 'Yes' or 'No' question. Ofcourse, it depends on how well you handle the situation. If you are a novice, you still need to read that thin line between when to tweak things, and when not to. Simple or stupid as it may sound, the answer is this: Change the topic. Yes. It works, and it worked a number of times for me. Whenever you are faced with this question, try shifting the conversation to another topic which is well related.
Unless you are good at it, try not to change the topic abruptly. Mostly, good one-liners are a great way to change the subject. That solves most of the questions and gives you enough time to come up with a good answer, or better yet, lets you escape while the other person is still laughing because of your witty reply. I just make sure that I don't lie unnecessarily. Sometimes one-liners just pop out of the head. Sometimes you hear something but you change it to suit your style, your way, and then you might use that somewhere.
A word of caution. This is only for situations where you have to really get out of. Where you really don't want to say a 'yes' or a 'no'. In case you use that often, it would be paradise lost. And better not cheat. Broken hearts spell doom to your relationships and it costs a lot. Plus you'll be hurt too.