Perhaps you want to take a trip to the local town to get your pictures developed or just sit outside and socialize with the others. You might want to go and play tennis or to relax with a book you found at the kibbutz library. Evening and who knows how late at night , when it's fun time. Evenings are not necessarily a party as you know it from home. You normally don't feel like dancing every single day anyway, and beasides, remember that you'll be part of a group of people with very different backgrounds from one another.
Evenings can be rather wild as well as rather quiet.
Sometimes with a lot of drinking and dancing, some other times with a guitar and a bonfire. Perhaps a big waterfight one night and just chatting and playing cards the night after that. Eventually some skinny dipping at about midnight, or a visit to some kibbutz family. All of this things take place, but none of them is a rule. It is all very spontaneous.