(1) Holiday celebrated every April 24th, involving the drinking of at least 24 beers. Any scheduled activity (e.g. work, classes, baptisms) must still be attended.

(2) An act of stupidity involing significant drinking, similar to the "yoke challenge".
"Did you see Chauncey? He just finished Newman's Day and looks f*cked up!"

"We were so bored we decided to pull a Newman's Day last night."
by Tastey Taste April 7, 2004
Get the Newman's Day mug.