eve celebration; pre-event festival; event held the night before
Refers to a celebration, program, or related event held on the night before a main festival, tournament, ceremony, or similar occasion. It can also refer more broadly to the eve of a festival or holiday.
A band performed at the school festival's eve celebration.
All the athletes attended the event held on the night before the tournament.
They held the eve celebration for the festival in the park.
Many tourists took part in the eve celebration.