The Indianapolis 500 is happening this Sunday . . . and you can count on one thing:  The winner will get a bottle of milk.  And sometimes they'll just pour it over their own heads, which seems a little gross.

You might know the story behind that if you're a die hard racing fan . . . or a die hard milk fan, I guess.  But for everyone else, here's the reason why you'll see the winner have a sensual moment with some dairy this weekend.

The tradition  was started by Hall of Fame driver Louis Meyer in 1933.  He'd just won the Indy 500 for the second time, and he requested a glass of buttermilk.  Then, after winning for the third time in 1936, he was given a whole bottle.

A photographer caught him swigging from the bottle while holding up three fingers for his third win.

A local dairy company saw it . . . and not realizing that he was drinking buttermilk, they thought it would be a good marketing move to present the winner with a bottle of milk every year, except between 1947 and 1955, for some reason.

The American Dairy Association of Indiana has special "milk people" in charge of obtaining the milk, and delivering it to the winner.  And prior to the race, the drivers mark their preference:  Whole milk, 2%, or skim.

Sadly, they can not choose chocolate milk . . . it has to be white.  They can opt for lactose free milk, although chances are the drivers who can't drink milk, or don't want to, are the ones who just pour it over their heads.