There are numerous clubs and student organizations at BIT Mesra. However, refrain from joining a club/organization just after club induction. First, find out the actual contribution of these clubs. Also, join the club that corresponds with your personal interest(s). Join a maximum of two clubs so that you can contribute well to them and attain a senior position by the time you reach your 3rd or final year.
As far as naming a few, I would mention just one organization at BIT Mesra that I feel everyone must be a part of. That organization is- Dristi. Here is how you can contribute to it as its member-
Thus, I would strongly recommend you join Dristi while at BIT Mesra, especially if you are interested in social entrepreneurship.