Team Fortress 2

1.1 - Teams are required to play with 2 players per match.
1.2 - Teams may have only one medic and one soldier on a team at a time.
1.3 - Ultiduo is played on KOTH maps.
1.3.1 - KOTH is played first to 2 round wins. The config used is cltf2_ultiduo.cfg. Links to custom configs are here.
1.5 - Ultiduo is played on this whitelist.
1.6 - Teams are allowed 3 players per roster.
1.7 - Teams can only have one ringer/merc per game. Check Match Rules 3.12 for more information on ringer/merc policy.
1.7.1 - During playoffs teams may not use the same player for multiple games.