How can I craft the Golden Wrench in TF2? seems like a perfectly legitimate question someone might want to Google, with an answer that won't change (with any more likelyhood than an SC2 or WoW question would).
There should be some distinction made between questions about one-off events with lasting effects and others that are meaningless after such a date (When is X coming out?) instead of just closing all questions that are somehow connected to an event.