Wack0 on GitHub has put together an incredible project: the ability to install and run select versions Windows NT on a handful of PowerPC Macs, including:

• iMac G3 (tray-loading)
• Power Macintosh G3 (Blue & White) “Yosemite”
• Macintosh PowerBook G3 Bronze Keyboard “Lombard”
• Power Macintosh G4 PCI “Yikes!”

A couple of videos showing the process have surfaced: