I haven't used it personally, but https://sneek.io/ https://sneek.io/ will do ad-hoc video chat. Those that aren't "live" on the call are still up on the wall o

I haven't used it personally, but https://sneek.io/ https://sneek.io/ will do ad-hoc video chat. Those that aren't "live" on the call are still up on the wall of faces, with a screen capture from their webcam every few minutes. Avoids the waste of unused video over the network, but still gives a sense of your teammates being live people going about their day.