Dec. 6 corresponds with our celebration of St.Nicolaas. On the evening of Dec.5 we celebrate this family-friends feast by unwrapping the gifts from st. Nicolas and Black Peter (his aid).
For kids up to 7 / 8 present the bagful of gifts is thrown over the threshold by a unnoticed temporary absentee of the gathered group or by one of the neighbours willing to do this.

Families with children over 8 fun give eachother gifts in diguised forms: the "surprise", pronounced the French way. This surprise should be a comment on actualities or merits or bad habits of the one who recieves the gift.
This fun side used to prevail over the importance of the present, but alas, money value is taking over everywhere.

There has been a political fight over whether ( fake) Black Peter should change color for reasons of discrimination. Fortunately this has passed and now real blacks join the Black Peter crowd (two or three weeks before Dec.5 many help-St. Nicolasses and Black Peters tour the country, scaring the 'bad' and cheering the 'good' children.

Why it is that in a predominantly Protestant country a Catholic Martyr has become the Saint of the season's gifts party no one really knows for sure. There is a famous Jan Steen ( 17th C.) painting showing the 'Sint Nikolaas avond' complete with a crying boy who got no present because he had not been good during the year.

There has been some competition between SantaClaus and Sinterklaas, but for now Sinterklaas still holds the lead. I know no of no other European country where Sinterklaas is really celebrated. (?)