Port 666 Doom

The number "666" has obvious connotations. For this reason, it was chosen as the port number for "Doom", a popular 3D "first person shooter" game of the mid-1990s.

Because of the cool connotations, this port number has also been chosen for numerous Trojan Horse/backdoor programs.

Quake game ports-There are lots of derivitive games of id's 3D engines. Trojan: Attack FTP