1. Similar to totalitarianism, brotalitarianism occurs when a (most often heterosexual) man's job, social life, and love life are taken over by his bro(s), a man (or men) who often has crazy or elaborate plans.
2. When a high school or college party is taken over by 'bros', a group of dumb jocks. Activities of a brotalitarianist party consist of smashing things, drunkenly hitting on virgins, and smashing things while drunkenly hitting on virgins.
The relationship of Barney Stinson and Ted Moseby (from the tv show How I Met Your Mother) is an example of brotalitarianism.
Dude 1: so how was Kimberly's party?
Dude 2: it was pretty lame until some brotalitarianists crashed it.