Historical clue formulations

• Celebratory opening — 2026-06-20
• "Time to celebrate!" — 2024-07-21
• "Time to light it up!" — 2024-07-05
• Bacchanalian cry — 2022-05-04
• Reveler's cry — 2019-01-25
• Fraternity house cry — 2014-10-25
• It may be said while wearing a toga — 2013-12-28
• Fraternity cry — 2008-12-05