Use 'saturnalian' to describe events with a lively, party-like atmosphere, often with lots of people. The carnival was such a saturnalian spectacle, everyone was in high spirits.
Pro Tip 2/3
Loud Celebrations
'Saturnalian' suggests noise and excitement, like loud music or people laughing and talking heartily. The streets were filled with saturnalian joy during the parade.
Pro Tip 3/3
Excess and Abundance
Use when describing events with an abundance of food, drink, or general merrymaking. Their wedding reception was a saturnalian delight, complete with a feast.