If so, dirabanan or diorayta? As far as I can tell from reading igros moshe, there's 3 issues: does the holiday constitute avodah zarah, it there a b'chukotayhem lo taylaychu prohibiton here, and lastly is it bal tosif? Rav Moshe pretty much summarily rejects 1 and 3 but leaves 2 as being problematic but not necesarilly issur here and finishes off with saying a ba'al nefesh wouldn't celebrate it. Curious to hear what you folks have learned on the subject. And please don't link to the Michael Broyde article.