Business schools want their students to be involved -- in class room discussions and out-of-class activities. You should aim to project through your essays that you are the types who will make the most of everything that the school has to offer.
All schools have clubs and associations that meet different interests of their students. Research school websites and identify those that will benefit you in your career pursuits and in developing soft skills that you plan to improve.
It's not enough to simply list the activities of your interest. You have to sound convincing that you really plan to be involved. It's not easy to do this because the course curriculum is demanding and can take a lot of your time. Successful applicants are able to project their time management skills; not necessarily by directly addressing the issue. You can sound convincing if you show that you have successfully pursued your passions and interests despite your demanding work commitments.
You are probably aware of the need to write about your involvement in extracurricular activities and community work. By writing about your extracurricular activities you would be able to show that you are likely to be involved in activities even during your MBA. The extracurricular involvements you choose to write about better be current. If you choose an experience that happened four or five years back you are in a way suggesting that nothing new has happened in your life outside of work, probably because lately you have been too bogged down by work. But this is not something you want to project therefore try choosing experiences that are relatively recent.
There is another benefit of writing about the clubs and associations that interest you. You can show your interest in contributing to and making use of activities of a specific club as a reason for applying to the school. Think about the networking opportunities that can come your way and how you can stay current with developments in an industry of your interest during two years of your MBA.