Kolęda - Christmas carol. Also: annual visit of the priest from your parish. Also: Polish version of Halloween trick-or-treat game, but the costumes are different.
It starts immediately after Xmas, and lasts until very last family is visited. In my parish a priest announces every Sunday which streets will be visited in the following week.
Not until very last family is visited. It is supposed to end before Candlemas.
cjjc: basically the priest, together with 2-3 altar boys and sometimes some other helper (vicar, organist etc.) is supposed to visit every household in his parish every year.
As not everyone is keen to experience such visit the procedure might differ: some parishes require you to put your name in advance on the list of people who want to welcome kolęda visit (especially in large cities where in general it is expected that there may be many reluctant residents). Sometimes the priest just rings the bell - and if noone answers he proceeds to the next door / house. Again, in general, if there is K+M+B mark on the door it is generally assumed that you are catholic and you would like to see the priest.
If the parish is quite large there may be a few different priests visiting the households. It also looks different in the cities (there are many people to visit in relatively short time and they live close to each other) and the country (there might be fewer people and they are scattered on larger area - remember that the winters in Poland can be quite harsh and travelling between farms is not particularly enjoyable. That also means that the priest will probably enjoy a vodka short once he arrives :D ).
In general it's all about small talk, maybe small cross-examination of the little children on how well they do with their religious education, blessing for the house and the family members (they should get the holy water in advance from the church) and last but not least - an envelope with money contribution. As this is split later on it comes as no suprise that assisting the priest during kolęda is one of the greatest priviledges for altar boys and matter of tough competition between them :)
Also, at the end of the week the priest sometimes stays a bit longer in the last household he visits, has a dinner there etc. and this dinner might be attended not only by the family members, but their friends and neighbours as well.
The annual pastoral visit (kolęda) is also an opportunity for the priest to update the parish records. The household's composition may have changed since last year through a birth, death, someone moving in or out, etc., so this also plays the role of a parish census. Above all the priest is prepared to discuss any family problems householders might raise --substance abuse, juvenile deliquency, uneymployment, illness, whatever.
Kolęda is a form of carolling. It starts after Christmas and can go on until Candlemas. It sometimes blends in with carnival guising as well.
It's form might differ in different areas but it is generally a bit like British Mummers plays. Kolędnicy often dress as different charcters, King Herod, Death, The Devil, Jew etc. They go to houses and perform songs, dances and perhaps a short play about Herod being taken by Death.
In some areas there might also be a 'Szopka' puppetshow.
It can get pretty rowdy. In the old days it wasn't unusual for soot to be thrown across the house. The people in the house would give food or money (I've heard of alsorts going in the same bag... cakes and bloody, raw meat etc). I heard of one kolędnik who told his wife not to let him and the others in because the house would get trashed. Needless to say, a fair amount of vodka would be consumed.
These days it still exists but often it is done by kids or theatre groups.
Found this on Youtube: uk.youtube.com/watch?v=eV1uiDpAL9s
There's a scene in the film "Chłopy" (is that spelt right?)