Blue Lightening Blast, Alienade, Orange Xplosion, KZ3 Battle Fuel. The 7-Eleven Slurpees has come a long way from its humble beginning as an over-chilled soda. Every year enough of the onomatopoetically named Slurpees are sold to fill up 12 Olympic-sized swimming pools. And today — July 11 (7-11!) in celebration of the store’s 85th birthday — they’re on the house.


The chain expects to hand out 7 million complimentary Slurpees this year, more than tripling last year’s number of 2 million free frozen sticky drinks.


Zany flavor inventions and marketing blitzes aside, the Slurpee hails from simpler times, more "American Graffiti" than "Alien." The concept was created by accident in the 1950s when the soda fountain at Omar Knedlik’s drive-in restaurant in Kansas City fizzled out. He began putting bottles in the freezer to stay cool, but the pops became slushy — and customers loved them. The clever Knedlik built a machine employing an automobile air conditioning unit to create the slushy drinks by combining and freezing a flavor mix, water and carbon dioxide. This led to his partnership in manufacturing the ICEE machine, which 7-Eleven licensed in 1965. The name Slurpee was coined by a 7-Eleven ad agency director, describing the now-iconic sound of slush being sucked through a straw.


And although the chain has branched out with some natural-sounding flavors, like Goji Berry Cherry and Peach Dragon Fruit, don't be fooled. Slurpee drinkers may want to know that the primary ingredient is high-fructose corn syrup. That said, since the drinks are airy, the calorie range of 60–70 for an 8-ounce serving is less than a conventional soda.


Check 7-Eleven's store locator, and call the location nearest you to find out if it's participating in the celebration.