Ask HN: Virtual Team Building?

My remote employer has horrible communication among developers. Almost non-existent. In the long term, this hurts both the company and its employees. If it doesn’t change, I will be looking for a new position, as I am a senior/staff level engineer and feel like my professional growth is stagnating. That said, I still hope to learn a thing or two from this scenario, no matter the outcome.

To wit, I am looking for open source tools that can be used to increase communication and collaboration among my team and across the organization. It needs to be OSS as it will be deployed on a spare machine as a side-project, in order to bootstrap management buy-in. A prototype that yields proof will be worth more than a story.

I am looking for the virtual equivalent of trust falls, bridge building, and similar interpersonal relationship and team building scenarios. What does your remote team do to onboard/revitalize developer communication? What solutions would you like to try or would be sure to avoid in the future?

To be clear, I do not want planning, scheduling, and other kinds of systems that would be useful if we actually communicated better. We already use such systems, but their efficacy and utility would benefit tremendously from better overall communication.