This celebration has evolved into a yearly event, which is visited by natives and foreigners alike. From a trusted source in München: compared to the other festivals, such as Frühlingsfest (Spring Festival), which is populated by almost exclusively young people and foreigners, Oktoberfest is an activity that all ages participate in. It is a very lively place with a lot of drunk foreigners and locals. In my own experience, you meet many new people, and there are rides like a mini American theme park.
Concerning Catholicism and Christianity at large in Bavaria, there are a lot of public holidays that are rooted in the Christian tradition, and everything is closed on Sunday. This is partly because Bavaria has historically been a very Catholic region of Germany but also due to Bavaria having a different work culture than other regions of Germany.
These traditions are both visible in the environment very often. On the one hand, it is a rare occurrence in München for there not to be some sort of public event, namely festivals. These take place at designated areas in the city. On the other hand, the degree of Catholic-style churches and monuments makes it hard not to run into Catholic-style traditions in München.
