Elade suggested doing an Arah run for shits and giggles (my words, not hers) as a guild in part because she was reminded of zombies and Halloween and in part because she just likes Arah. Given our past experience at giving Lupicus two extra nuts to juggle, I think it should be relatively straightforward.
I'm asking on her behalf because I think she's under the impression everyone hates Guild Wars 2 and refuses to play it with her. I tried to argue that it's the fault of ArenaNet's developers having no interest in permanent content but failed to convince anyone in that regard. I may have also mentioned something about the vernal equinox.
As to the time, I have no real preference--nor to the date--provided it runs no later than 9-10PM on a weeknight, but weekends would in some ways be moderately better.