Floppy Burger is a fast food establishment located near Third Street School. Although it's not the gang's primary after-school destination (Kelso's being the primary), they have been known to visit as mentioned in "Kurst the Not So Bad".
Every year, Floppy Burger serves a specialty dessert for the first week of spring known as the Shillelagh Sundae Which is composed of seven scoops of green ice cream, green fudge syrup, green whipped topping, green peanuts, and a green cherry. This dessert is implied to be overly sweet as The Recess Gang confesses to Mikey that the Shillelagh Sundae makes them sick and even vomit as also implied by Gus as his mother made him "promise to never eat one again after what happened on their living room carpet". Kristen Kurst also comments that the Shillelagh Sundae makes her friends sick as well.