There's 'never a dull moment' in our house. [=our house is always very busy or exciting]
The conversation was 'as dull as dishwater'. [=('Brit') 'as dull as ditchwater']
The book is 'as dull as ditchwater'. [=('US') ('as') 'dull as dishwater']
(..) What are you doing? Okay, so listen up. I was thinking since, Brad, you were saying... how your wedding was gonna be all poor or boring or dull or whatever it was you were... You said our wedding was gonna be dull? I said it was gonna be small. Small! Yup, that's exactly what it was. (..)2009 TvShow: It's Always Sunny in Philadelphia Title: The Waitress Is Getting Married Season: 5 Episode 5