I wasn't aware that there were 'hosts'. they were not obvious anytime I was there. It seems to be just show up and see if anyone else is there and singing. Someone posting a thread saying "now" usually gets people there. So on Halloween Eve (and/or Halloween Nite) show up when it is comfortable, so Europe and Britain would probably start earlier, and be prepared to sing Halloween, ie ghosts, monsters, supernatural, scary songs. That seems like enough planning to me. Unless someone wants to do more...