We did it on Navigator. I'm sure each ship would do it a bit differently. It was fun; I particularly enjoyed the chocolate tasting, although the presenter, albeit charming, was a bit inexperienced. Don't get me wrong, he knew his stuff, just not a really great presenter. He was with Valrhona, wich was the chocolate company involved.
Although not blown away by it, I did find myself wishing that our upcoming December cruise was chocolate again. I also have become a dark chocolate aficionado for the first time in my life.