My old fcs did a lot of things such as

Night at the Gold Saucer: Self explanatory

Hide and Seek: pick a ward and go nuts

Price is right: Get a marketboard item and guess the value, usually this one involves prizes so not recommended for
New/poor fcs

Human Darts: take your brightest mount and have players land on you in the Astrolegon towers in Coerthas

PvP duels: this one will require some restraint cuz a lot of my Old Fc mates take this one very seriously

Virus: Just like hide and seek but starts out with one person and once he’s caught he joins whomever is “it” until 1 remains , playing this with 36 players online in The Lochs in Gyr Abania is super fun but stick to smaller locations if you have smaller fcs

Treasure chests/Farms: the more basic things to do but effective if you have charismatic members