A sundae is a delicious ice cream concoction that might include hot fudge or caramel sauce, nuts, and whipped cream. You can order a sundae any day of the week.
When you put ice cream in a dish, drip a sweet topping over it (like strawberry sauce or chocolate syrup), and add a dollop of whipped cream and a cherry, you've got a sundae. There are several competing stories about the origin of the sundae (and its name). One is that Illinois' outlawing of soda drinking on Sundays led to the dessert's invention. Several towns claim to be the sundae's birthplace, including New York City; Plainfield, Illinois; and New Orleans.