Which of the following games was NOT included in Valve's Orange Box?

The game that was not included in Valve's Orange Box was Counter-Strike. While the Orange Box was a compilation of popular games released by Valve, Counter-Strike was not part of it. Counter-Strike is a highly popular first-person shooter game that was developed by Valve, but it was not included in the Orange Box bundle which consisted of games like Half-Life 2, Team Fortress 2, and Portal.