An annual holiday for men to celebrate the anniversary of a stag party by leaving the confines of normal life behind and religiously obeying only three rules:
a) No-one is a stag;
b) Everyone is a stag; and
c) Everyone behaves like a stag
"HAPPY SPAWNIVERSARY, BRO! I got you a case of Laphroig 21."
"Holy ferkin' snit! That must have cost a fortune!“
“It's all good, I have a grove of money trees, and no kids."