My daughter enjoyed playing "Doctor" when she was around 3, complete with a stethoscope and pretend medicines she had to administer to her "patients." It taught her about the importance of helping others and keeping them well, and she also learned some basic body parts and health-related vocabulary.
Another one she loved was a "Marketplace" role-play. She set up a makeshift shop with her toys and Mock cash register (which she insisted on being able to scan items and count the change). Role-playing different careers - teacher, chef, or even veterinarian - helped her understand the concept of money and introduced many community helper vocations.
These themes are great fun and can be adapted for different ages with varied difficulty levels!