Australia's most famous horse race, the Melbourne Cup, is the race that stops two nations.
And while workplaces may halt to a standstill at 5pm tonight, Internal Affairs is warning bosses on how to keep their sweepstakes by the book.
Office sweepstake prize money cannot exceed $500, which means tickets for can cost not more than $20.88.
And for anyone with an entrepreneurial streak, any money raised must be returned as prizes and no one is allowed to profit from organising the sweepstake.
Violating these regulations could incur a fine of up to $1000.
And beware of offering banned prizes. Firearms, liquor, tobacco and vouchers for sex services are all prohibited.
"If you are thinking of running a sweepstake you can – the hurdles are not too hard and make a lot of sense— but do make sure you understand and comply with the rules," the DIA warned yesterday.