Stream your current screen content to another computer using ethernet or wifi network.
Run this App on your Mac, you'll get the http address, now open the address with web browser on remote computers.
Yes, you are broadcasting your screen in real time, no matter you are playing games, watching videos, or teaching courses etc.
To Windows user: IE didn't support MJPEG video by default, you need to install MJPEG plug-in for IE. Or you can use Chrome, Safari instead.