Ravenshaw has quite a few clubs and societies you can be part of. Some of the popular ones include:
Theatre and Drama Society
Debate and Literary Club (PRIDE)
Film Society (FSR)
Art and Culture Clubs
Ravenshaw Radio 90.4 FM (yes, the campus has its own radio!)
Sports teams include cricket, football, badminton, etc.
NCC, NSS, Red Cross, and even an IAS Study Group
And about using tablets in class – yes, you generally can. Most teachers are fine with it as long as you're using it for classwork or taking notes. Just double-check with your professor in case they have any specific rules.