At the request of Abrasivist, here is a cursory background on "nickel beer night," also called 10-cent beer night because everyone was too drunk to remember exactly how much the beer cost during the 1974 game.
It was the Indians and the Texas Rangers at Cleveland Stadium. Needless to say about the Indians in the 1970s, but they were desperate to boost attendance, so in what was probably a fairly common practice at the time, team management decided to lure Clevelanders to the game with cheap beer. And if you know Cleveland, you know that's like setting out a bug zapper to catch mosquitos.
A quick check of the Internet showed me no detailed chronology of the events of the night, but I give you a bit of the flavor from memory.
(It should be noted that I was born in 1979, so I have no firsthand memory of the events, only newspaper accounts and old footage.)
Somehow, over the course of the early innings, the relationship between the fans behind the visiting dugout and Rangers players became rather chippy. I can't remember if fans actually started running onto the field at one point, or if they simply began tossing beer bottles onto the field, a la Cleveland Browns Stadium in 2001.
Whatever happened, Rangers manager Billy Martin soon decided it was time re-enact Pickett's Charge and led his players onto the field. Martin's paramilitary antics only encited the drunks in the crowd further, and before long, people were indeed running onto the field, confronting Rangers players fist-to-fist, and the game got out of hand.
After police couldn't restore order, much like during disco demolition night, the American League forfeited the game to Texas.
Even though Martin led his players onto the field, the Indians were the ones ultimately responsible for maintaining order in their home stadium, so that's why they lost.
Martin's antics that night don't get a lot of play in the media because everybody primarily remembers his five managerial stints under George Steinbrenner and the circus that caused. But nickel beer night, though started by drunk fans, might be the best example of Martin's notorious temper making a bad situation worse.