During the week we can go from 5 - 7 PM CET, and on Monday, Tuesday, and Thursday from 10 - 12ish PM CET. On weekends maybe since 2 - 7 PM CET and on Sundays after Domi. On all days from 7 - 10 PM CET some people can sign up when they're not in AS.
There's just so much to do with dailies, in game events, and raids.