So this one is pretty straightforward.
Go to Aldebaran and talk to the snow festival manager at 174, 164 and he will ask you to join in on the festival. You get a few options, one gives you background info, but the first option selected starts the quest. He asks you to collect magical snow flowers dropped from snow boys.
Snow boys are plant-protocol event monsters that use the Siroma sprite which are spread on field and dungeon maps. They drop Ice Candy (save these) and the magical snow flowers. You'll also find myst cases and porings. The Myst Cases drop envelopes which give you blue letter cards. (not sure what these are for yet). The porings can drop costumes at a low rate 
Anyway, get the 10 snow flowers and go back to the manager and he lets you make a bouquet out of them and present it to one of the snowmen. You then get 10 ice candies and 5 prize boxes.
You can then do the daily (I think daily!) quest with the snow flower illusionist (frozen mage guy) which requires 10 magical snow flowers + 1 carrot for some more ice candy and another prize box.
Also, the NPC named snow (guy in red coat near the benches) will give you a prize box for 3 ice candies (useful!).
The Ice candies are a very nice healing item, but since you can get xmas costumes with effects from the prize boxes you may want to trade them in.
The blue cards can be used to spell FLOWER at the very north east of Al De Baran for more candies and boxes by talking to twinkle. They give you 5 candies and 3 prize boxes. (this one seems like it will have multiple words as there are cards to spell SNOW, FLOWER, and FESTIVAL). If you do this 5 times on the same char you get the costume 'Let It Snow'.
At the north center exit of Al De Baran are two child NPCs that will give you another quest to collect 'cotton' which you automatically get when killing the monsters they list (fabre, skeleton, marin, lunatic, etc.). They give you 5 candies and 1 prize box.
Most of these seem to be daily quests as they tell you to come back the next Dawn, but no quest entry.
The prize boxes can contain some generic candy or cookie items, but also the ice candy items (3 of them, at an equal exchange rate for the prize box), the snowman cookies which give pretty nice buffs, or christmas costumes (including some that have effects).
Mod Edit - VModCinnamon:
Discarding Blue Cards
Users wish to remove their Blue Cards to speak to NPC Festival Claviger in Eden by the kitchen entrance, they will take all of your Blue Cards. In case they did not clear all of them speak to Gramps once.
Edited by VModCinnamon, 30 January 2018 - 06:25 AM.
Added discarding blue cards note.
