In October, Norwegians to a lesser degree celebrate Octoberfest and Halloween (although you can easily find people who do in smaller cities).
There is one tradition, however, associated with fall. This is høsttakkefest - traditionally a celebration to thank God for the harvest. The word translates fall - thanks - party (not to be confused with the American thanks giving!)
Høsttakkefest usually takes place in Primary Schools, where children are asked to bring one vegetable each, and then they cook a meal together.
Best,
Hannah, Community Manager - Norwegian