Both The Longest Yard and Facing Worlds can now be played instantly on the web:

https://thelongestyard.link/q3a-demo/ (instant, even works on phones)

https://dos.zone/mp/?lobby=ut (scroll down and click Create on CTF-FACE)

They even have multiplayer support.

I hope someone ports UT2K4 someday so I can play ONS-Torlan.