Similar experience on Sirena a couple of years ago (special menu, funny hats, horns, etc.), but with an unwanted "extra". We had retired early after a long day. At midnight, the captain decided that everyone needed to celebrate, so did a live countdown on the speakers in every stateroom (not just in the hallways, as usual with announcements). Woke us (and I imagine quite a few others) from a sound sleep. It was very loud, and no way to turn it off. I don't know if this is standard procedure for New Year's on O, but you might want to be aware.