Since I spent way too much time ripping images on XII I found some ways to make it even more amusing. Here are my tricks:

Fran almost falling on her butt:
You know when you run with your leader and do a full stop they kind of bend their knees and slide a little ? With Fran's high heels and the Paramina Rift ice the slide is even more noticeable and funny: Make her the leader while at Paramina rift and run towards an ice patch. Stop abruptly.

Onion Head Toss:
Basch with a big sword is best for this: On Phon Coast run after those onions and hack them. If you get your strike just right the poor thing will fly into the air, flip and land on it's head.

Vaan swinging like a monkey:
Equip Vaan with a two handed greatsword for a boss fight. Watch him swing then sit on top of it after the battle ends.

Psycho bunny:
Heal one of those cute bunnies in the Giza Plains and watch it turn hostile, attacking your party.

Any funny stuff you like to do during the game ?