Similar to the popular children's game 'buckaroo', where you take turns to add small loads onto a toy mule that eventually kicks everything off, at which point the person who was in the act of adding something loses. 'Drunkaroo' tends to happen at social functions where there is alcohol a-plenty. When one member of the party reaches the stage of passing out due to excessive consumption of alcoholic beverages, they become the mule, and the rest of the assembled group get ready to play drunkaroo. Turns are taken at placing things on the mule like coats, bags, full pint glasses, furniture, etc, until at some point (s)he comes to, throws everything off in an angry drunken sulk, and then more often than not rolls over and passes out again, at which point you can play the next round. Happy days.
Sweet, Ellie has passes out again, lets play drunkaroo.
or
me: we've been playing drunkaroo with bryan for about an hour, and there's nothing left in the house to put on top of him.
mikey: nothing that is, apart from the sofa.