Here are some things you can do at NIT Calicut to make the most of your free time-
To keep yourself busy, you can join karate classes. This will keep you active. If you are into video games, you will always find others to join you. You can watch late night movies and tv series with friends. You will surely end up cooking some maggie in your kettle when late night hunger strikes. You can go cycling during the weekends, in the morning. But make sure to take proper care and use proper bicycles because the roads in Kattangal are very steep. Apart from all this, if you wish to explore a bit, you can visit IIM Kozhikode or Munnar/ Kochi.
All that I listed up till now are fun activities. But for a more productive weekend, you can read novels or take part in quizzes and prepare for those. You can also be a member of a club at NIT Calicut. By organizing club events, you can connect with various people and learn management skills.
If you are a CSE student, your workload will be quite less at NIT Calicut. Thus, you will get plenty of free time. You can use this leisure time by participating in extracurriculars, learning a new skill and making memories with your friends.