Following are the points I.can think of:
1. Distributing sweets and chocolates on festivals.
2. Making them things that they want to learn. In which the kids have interest. Eg painting, dancing, drama etc.
3. Organising a small sport activity in the campus where the kids are living. Eg race, sack race, badminton, musical chairs etc.
4. Taking them to a trip on places nearby such as red fort, india gate etc.
5. Doing some small hilarious dramas and dances in front of them so as to create the interest on them.
It might take time but I hope it is worth doing it.