Every year, after the holiday parties and new year's eve toasts, I quit alcohol cold turkey for the entire month of January. I don't do it to prove that I'm not an alcoholic -- really, I'm normally just a moderate wine drinker -- I do it because I want to clear my body of the alcohol toxins that I know I draw in during all the end of year celebrations. Also, it just feels good. In fact, so good, after that first January that I swore off alcohol, I decided to stop for another month during the year as well.
So, for the last 15 years or so, I'm alcohol free in January and July. It's a great break, and it even helps me lose a pound or two in the process.