The best activities for a project wrap-up combine recognition with release. Recognition for what was achieved, and release from the pressure the project required. Proven set-ups: a retrospective followed by drinks, or a team dinner at a good restaurant. An outdoor activity with a shared meal works well too. As does an escape room or an unexpected outing to a concert.
Always build in a personal moment: name people, celebrate specific contributions. That's worth more than a generic 'well done'.