Sometimes rekindling an old flame turns out to be a good thing. Take everyone's favorite "Awww" couple, Ryan Gosling and Rachel McAdams, who are reportedly starting things up again after a year in splitsville. Other times, not so good: Nicollette Sheridan and Michael Bolton just called it quits the second time around, announcing that they are no longer engaged.

Most of us have at least one ex we just can't get over. And then, as luck would have it, they pop into our lives again. We forget why we broke up with them in the first place (or why they broke up with us, but who's keeping track?). We consider giving it another go. Can the second time be the charm, or do we tend to just repeat the relationship's mistakes?

Tell us! Have you ever given an ex another chance? Did your second experience teach you any lessons you missed during your first time around? Should your past stay in your past?