I think something to do with fashion week was the original call for Rarity day, but I have no idea so lets just celebrate Rarity anyway!
On the 8th of the month, we post all the Rarity. Get your submissions in for her! Open art in particular!
To submit, send an email to submit@equestriadaily.com with RARITY DAY followed by what it is, so RARITY DAY - OPEN ART for open art. Submissions close at 11:59 PM PST on the 7th of September, so be sure to get them in quick! I won't be able to take many late submissions.