posted on 3-1-2003 at 07:24 PM
Aside from the ever-present Day of Honor (which has it's own thread going), I've seen references to:
QI 'LOP at "tlhIngan Qummem"
: Klingon major holiday (n) * which comes every tenth Klingon month. Like most Klingon holidays it is marked by much eating and drinking . It is also marked by a peculiar custom; Each guest brings a large dish of TO'BAJ 'US - stuffed to'barg legs to the hosts house. In return the guest is allowed to take any non-sacred item in the house. The actual origin of this custom is obscure. (I thought it sounded like KEPLO' ) .
* = non-canon or non-verified
and the: Feast of Qot baVol at "Totally bIj issue #18"
. Not much was given in the way of specifics. I don't know how widespread it is; it may be a tradition observed solely by the crew of the IKV Stranglehold.
As for a New Year celebration, Klingon history seems defined more by major battles, events that relate to successions, etc -- political history, as opposed to natural history involved in the regularity of planetary cycles or astronomical events. Also, IIRC most Imperial calendars throughout the ages use as reference points the reign of a particular ruler or dynastic line. Thus I doubt such a tradition of New Years based on something as "boring" and predictable as the path of a planet around it's sun would be widely observed.
But it's a big Empire, composed of many conquered worlds and peoples with differing customs. So who knows?