Choose the game first
Open Sports or Group Games, choose a playable activity, and make sure everyone understands how the round works.
Activity first
Choose a real-life game, agree on the rules and winner condition, then let participants choose any $STUD amount before play.
Open Sports or Group Games, choose a playable activity, and make sure everyone understands how the round works.
Set the rules, winner condition, and participant-chosen $STUD amount before play. Do not add hidden terms after the round begins.
Play the match under the agreed rules, call the result clearly, then participants settle the chosen amount between themselves.