It refers to an act of pure comedy or dry humor. It refers to all Donahues, but more specifically the talk show host Phil Donahue and relative Will Donahue. Any one can pull a classic Donahue
"Hey did you see what Will did?"
"Yea he made that whole group of people die in laughter."
"Oh Classic Donahue!"
Donahue is an Irish last name, which usually means that they are someone is in a somewhat large family where usually a member has anywhere from 1-11 siblings and somewhere between 12-36 first cousins and 56 second cousins. Donahues usually reside in the United States with most of it's members in the mid-west and some stray ones in places like California and Florida, or in Ireland.
Mr Donahue is the nicest and best history teacher ever. He is a financial wiz and will sell the whole stock market to you. He drives around in the top model of the Honda Civic even though he could be driving a Mercedes. He is all in all a good teacher.
His favorite word is Obliged. He also likes to refer to his clothes as threads and tries to be chill when he complains about shit on facebook. He also likes to argue with other fags about sports because they think they are so educated.
Joe Donahue - "What do I do when I'm bored...go peck flex in the mirror...hahaha :)"