Are there any phrases like "Couldn't organise a piss-up in a brewery" or "Couldn't organise a root in a brothel" that are reasonably common, indicate organisational incompetence, have a degree of irony (as opposed to "Couldn't run a chook raffle", or answers to the more general question Is there a proverb or idiom describing incompetence?) and aren't vulgar?
Wiktionary suggests couldn't organise a bun fight in a bakery, and while it does appear in real life (example: Brisbane port ready for naval expansion), it doesn't appear to be common. Are there any that are non-vulgar and are more common?
Related, but not as specific in its requirements: Is there a proverb or idiom describing incompetence?