Today is a special Sunday, this is particularly because it's the 119th anniversary of the first documented ice cream sundae. Google has a special doodle to celebrate this occassion.
Surprisingly, the ice cream sundae had been invented accidentally. The urban tale goes that in more austere times the clergy deemed the popular dessert, ice cream sodas, to be 'too frilly' a food to eat on the Sabbath (naturally a Sunday). So, instead of offering an ice cream soda, ice cream was served with cherries and syrup drizzled on top.
"Some historians claim, but never proven to be true, that the name "sundae" was created in response to the "Blue Laws" which said that ice cream sodas could not be sold on Sundays because they were to "frilly." For some reason the "righteous" very much against what they called "sucking soda" (especially on the Sabbath and the clergy started preaching against them). The dish has gone by other names at various time, most notably "sundi" and "sondhi." Some accounts have explained all these names as attempts to avoid offending the sensibilities of the devoutly religious, which might take a dim view of a pile of ice cream and syrup being named after the Sabbath."
Source: Source: What's Cooking America