Modifiers matching occasion:

• dressy,
• formal,
• unique,
• particular,
• special,
• happy,
• joyous,
• personal,
• organized,
• solemn,
• informal,
• private,
• official,
• historical,
• emotional,
• significant,
• musical,
• oriental,
• exclusive,
• meaningful,
• joyful,
• celebratory,
• social,
• unusual,
• large,
• single,
• important,
• big,
• sad,
• elegant,
• public,
• serious,
• memorable,
• major,
• outdoor,
• wonderful,
• upcoming,
• extra,
• extraordinary,
• festive,
• stressful,
• auspicious,
• romantic,
• crowded,
• infrequent,

Simple categories matching memorable:

• item,
• production,
• function,
• event,
• stuff,
• keepsake,
• episode,
• occasion,
• activity,
• holiday,
• date,
• experience,
• story,