FreeDisplay is a free application for mirroring your display to everyone on your local network (like your home WiFi). People can access a mirror of your screen through their web browser by scanning a QR code that is generated when you start the program, or by typing in the address that is generated in the window when you start mirroring. As long as they share a network with you, they'll see your screen in their web browser of choice for as long as you choose to share!
Download the Windows executable here
Unzip the zip file anywhere on your machine. Double-click FreeDisplay.exe and mirroring will begin immediately.
This is an open-source project written in Python 3. You can install the prerequisite packages like so:
pipenv install
python setup.py build