I'll continue with my story from the other thread and shall explain more about Sinterklaas in the Netherlands and indeed putting your boot or shoe out as
@bavaria said. It's similar to having your stocking above the fireplace for Christmas.
Sinterklaas arrives the 2nd Saturday of November in the Netherlands from Spain, he arrives by boat, this is aired on national television. From that day you can leave your shoe out and Sinterklaas leaves gifts. Preferably in front of the fireplace, but if you do not have a fireplace (I didn't have a fireplace when I was young), you can also leave your shoe at the front door, or even the central heating (as a kid this made sense). You leave your shoe out, and Sinterklaas will give you some small gifts, something that fits into a shoe. Usually it's chocolate. In return we leave some carrots with the shoe, for Sinterklaas' horse, Amerigo. Similar to leaving cookies & milk out for Santa. And yes, Sinterklaas rides over the rooftops on a white horse. Again, as a kid this made sense.
At my home, we were only allowed to leave our shoe out on the day Sinterklaas arrived, but I know some families do this every night till the 5th of December. My parents weren't made of money, so we only did it once
On the 5th of December, after dinner, your parents have asked a neighbour to knock on the door/window really loud, and then the neighbour goes into a hiding. When the kids go to open the door, there is a bag of presents, left by Sinterklaas., who is nowhere to be seen... really mysterious!
The presents come with a 'surprise' and/or a rhyme. This is serious business ;-) A 'surprise', it's the same word as in English, but pronounced as if it was Dutch, is when you craft a disguise for the present. This has to say something about the receiver or about the present. So let's say the receiver of the present is into soccer. Then with arts & crafts you create a soccer ball and put the present inside.
The rhymes are sort of similar, it's supposed to say something about the person or the gift. But since the internet was invented, we have websites to help you with this. Actually the first websites designed in the Netherlands were websites where you could create generic rhymes for Sinterklaas. The rhymes can put a lot of pressure on you if you have a lot of presents which all need a rhyme. You need your creativity. And then a website can truly help. In my home 'surprises' were optional, but every gift had to be accompanied with rhyme. The rhymes are usually funny, with puns, but you can also go for sincere. When you are an adult, celebrating with just adults, the rhymes usually get dirtier
What else...
The first Sinterklaas candy shows up in supermarket and stores around August, which is very annoying. Almost 4 months before Sinterklaas even arrives in NL!
Also I consider it bad manners to put up your Christmas tree, or sing Christmas songs before Sinterklaas has left the country on the 6th of December. Most stores do this as well. So Christmas decorations usually go up for only 3-4 weeks, and usually by the 1st of January everything is gone.
This year, we will have the arrival of Sinterklaas as usual. But it will be a secret where this is going to happen. Because when he arrives, this attracts huge crowds. Each year, he arrives in a different city, and it's considered an honour to host this party. It's considered good publicity for the city.