couldn't organize a piss-up in a brewery

couldn't organize a piss-up in a brewery

  (British & Australian very informal!)
if someone couldn't organize a piss-up in a brewery, they are very bad at organizing things
Usage notes: A piss-up is a social occasion where everyone drinks a lot of alcohol, and a brewery is a place where beer is made.
For god's sake don't ask Martin to make the arrangements. He couldn't organize a piss-up in a brewery.