The details of the Yamanote Halloween party have been released and are:
Saturday, October 28 JR Shinjuku station, platform 13 (Yamanote bound for Ikebukuro) Meet where car 10 stops, in front of the escalator from South exit Everyone boards the 21:07 northbound train and loops around clockwise BYOB, or better yet, whisky.
See you there? Now, for some kind of costume!
UPDATE: On second thoughts: I was standing, being battered, in Shinjuku Station, waiting for some friends this evening (Saturday), and I suddenly realised: I absolutely, totally and completely detest crowded places. What ON EARTH am I thinking? It'll be horrendous. It'll be rush hour with no place to pee. Funny how things sometimes seem such a good idea, until you really stop to think about them, isn't it?