Same numerical rules apply (Rank 5, last number -- Rank 4, last 2 numbers -- etc. to Rank 1, all five numbers), except the methodology for picking a number has changed:
1) One number _per Square-Enix account_.
2) Once a number has been chosen, it cannot be changed.
Rank 1 prize this time: A RELIC OR MYTHIC WEAPON!
That's right -- all the relics and mythics are in play. Match all five numbers with your one choice, and you win one!
Rank 2: Basically look at most of the mega-money drops: D. Ring, Ridill, Hofud, Valkyrie's Fork/Coat/Breastplate, Valhalla Helm/Breastplate, Black Belt, Velocious Belt, and several others. (Full list is at the official VanaFest website, which you can access from the official POL FFXI site...)
Rank 3: Kinda the next step down, but still a whole lot of neat shit!!!
Ranks 4 and 5 will be announced at VanaFest, but it really sounds as if they're pulling out a few more stops for this event.
You can apply for your number Real Soon Now at the official VanaFest site.