Yeah, there's a variety of 4hr doff missions, with funny holiday-themed names. Critting them gives you a chance at the holiday "bits".
The snowman battle is every :00 and :30. Kill 100 of the small snowmen, and the giant one spawns. Kill the giant one, get some bits. Oh, and use Snowballs to do this. Equip them like a device.
The competitive (or "pvp") race is every :15, :22, :45, and :52. When the announcement appears, go to the starting area (west of the Gazebo), and it'll give you the quest for it. The prizes are Winter Epohh Tags, which can be used for a doff mission to gt an Epohh pet in holiday colors. (edit: and yes, there's currently a way to skip a large part of the track. Followed, after every race, by furious arguments about what constitutes "cheating" in a videogame. /sigh)
The daily race is for Q Photos, which will get you the Breen ship.
There are accolades for fighting the giant snowman (20 fights), the pvp race (20 races, or come in 1st), and for finding all the snowman scenes.
You can also (rare drop) get the holiday bits & Epohh Tags from digging up snowballs.
The bits can be traded in to the Holiday Vendor for winter foods (feed it to a tribble!), several new costume parts (scarves and jackets), snowball guns (to kill the snowmen), skating boots, and glowy melee weapons.
Those with Lobi to burn can get Q Photos and bits from 5-lobi-per boxes.
And finally, all the bits & tags (once it's over) can be turned in for latinum at the latinum exchange consoles.