My idea is a Sharing Post that would particularly suit apartments or townhouse complexes and provides opportunities for people to share produce. It could be a table with a notice board or even a defunct fridge or bookcase. Residents can leave handmade or home-grown items or even something they have plenty of. This would provide one step in creating a community feeling amongst residents.
A perfect resident event that's fun for kids and parents alike. A bonfire with all of the s'more ingredients provided, pooled together by community members. It can be a regularly recurring event. Get the kids engaged and their parents will join the party. Can also take the form of a community BBQ or a Potluck.