Official Game Files and Patches (Windows)
Enemy Territory is a completely free game, so have at it!
Enemy Territory v2.60b for Windows
Enemy Territory Minimizer Tool (CTRL+Z)

Official Game Files and Patches (MacOS)
Mac users will need both the game and the patch to play with UFG.
Enemy Territory v2.60-2 for MacOS
Enemy Territory Path to v2.60d

Official Game Files and Patches (Linux)
To install on Linux, unzip the archives. Chmod +X the .x86 file for the 2.60 installer. Run it in a terminal window. Then, unzip the patch and copy et.x86 and etded.x86 into your game folder. Then you're good to go!
Enemy Territory v2.60 for Linux
Enemy Territory Patch to v2.60b for Linux

Custom Maps
Killhouse (Screenshot)