Modifiers matching outing:

• frequent,
• quarterly,
• enjoyable,
• social,
• regular,
• casual,
• educational,
• inexpensive,
• special,
• expensive,
• monthly,
• corporate,
• simple,
• recreational,
• organized,
• seasonal,
• planned,
• optional,
• active,
• urban,
• communal,

Simple categories matching quarterly:

• outing,
• event,