I think it is different even in parts of the country, here USA, that is.

We celebrate on December 25th.

Usually have string lights on the edges of the house roof, around the car garage door etc. Yard decorations of the nativity, snow men, reindeer, santa some even "move" and lights on the trees .. inside and out.

Inside trees are often artificial, strung with lights, tinsel, garland, glass or plastic balls and sometimes only white lights etc or multi colors... gifts are put under neath the tree..if they fit. Holiday cards are put up on strings or on the tree inside. Holly is a big decoration.

Some go to church Christmas eve, some Christmas day and some not at all and some both. We sing carols in groups sometimes within the family... when I was little, ppl would go house to house singing christmas carols..

We exchange gifts... sometimes one to one and sometimes, like in a big family, have drawn names to buy just one gift. Some open presents on the eve, others the morning.. military families might wait days for the service man to come home (if he can) before opening gifts together.
Eating is always important. Some have turkey, some have ham... will "all the trimmings" stuffing, potatoes or yams, green beens or such, rolls... corn... and desserts! Pumpkin pie, apple pie, mincemeat, pecan.. ice cream... Egg nog is a popular drink.. often with a whiskey type alcohol added.

There's usually a parade to watch on tv.. (Disney comes to mind) and a football game to watch in the afternoon... all while munching on leftover foods.

I'm sure I left out plenty. Hey dublin.. tell about Canada, eh?