The Longest Night · 10:32pm Dec 21st, 2014
Today - at least in the Northern Hemisphere - is the Winter Solstice. AKA Midwinter or The Longest Night.
As the last name suggests it is the longest night of the year, and thus, seems likely to be a special holiday to Princess Luna.
Many bronies/pegasisters believe today to be the Winter Moon Celebration or even Her Highness's birthday. Personally I think Luna's birthday could be any day of the year. As for the Winter Moon Celebration... it seems possible, however there is one flaw in that there is not always a moon on the solstice. Where I live it is the new moon tonight, so we will not see the moon at all.
However, Equestria is quite possibly different, there seems to be a full moon every night. The only argument against that is the fact that Luna has crescent moon as her cutie mark, as well as Trixie, Night Light and some others. Well, that and the fact that it's a kids' show and also almost every show and movie has only full moons because they are more epic.
...I'm over-analysing a kids' show... Now I feel officially part of this ridiculous (in the awesome way) fandom. 
Anyhow, regardless, the Longest Night must be special to Luna, so all hail Her Grand Royal Highness, Princess of the Night! 
Hail Princess Luna! The great and glorious Princess of the Night!
Merry Christmas!
Jubilee
2668817
Aye brother, let us praise our Night Mother on this, the longest nigtht!
Also, Happy Christmas!
Hail Princess Luna!
Also, it's nice to see you again. After one of my other good friends quit FiMFiction, it's truly awesome to see another good friend of mine online again.
Hail Princess Luna! And happy birthday to her!
And Happy Christmas to you! 
For me would be Celestia's birthday today, as is Summer Solstice by here on Brazil and in my Hemisphere.
2668901
Are you talking about Blue Ice Tales? Yeah, I knew him too, though not very well mind you... I'm not exactly sure why he left.
I myself have actually been online every so often the last couple weeks. My internet problems are over, but I don't have much time for internet browsing any more, what with it being the Holidays and all.
You're one of my greatest besties here on FimFiction! (Though admittedly that's not saying too much... 
)
I'm glad to see you too!
Long live Princess Luna, and Happy Christmas!