I saw this game on youtube where you need to make a ball travel a certain amount of space using some half tubes. I was wondering where you could buy these kind of tubes or how are they called in english since I am not a native speaker
The brightly coloured stuff pictured was probably sold for the purpose, unless it was painted for the players to use.
The most readily available material in the UK (and other bits of Europe I know, but the only time I've been to Sweden was 30 years ago) is guttering, as used to collect rainwater falling off roofs. This should be available from most places selling building or DIY materials. A good size for this would be the smaller type often used on garden sheds and similar small outbuildings.