Downtown Abbey
When people mistakenly refer to the British drama series "Downton Abbey" as "Downtown Abbey". These are usually people who have never watched the series but want to have something to talk about to their smart/posh friends who like that kind of stuff, often in a bid to "fit in" or be perceived as normal in a certain environment. Easy giveaway when they claim to be an avid fan of it, yet can't even say it properly. Completely unaware of their mistake yet nobody mentions this to them as it becomes an inside joke whenever they say it.
Person A: hey everyone, did you watch the last episode of Downtown Abbey? I loved their portrayal of the Elizabethan era!
Person B: *whispers to Person C* now we know this guy is not really a fan of the show. Plus it's actually set in the Victorian era.
Person C: I know right! Let's just play along though, for fun.
Person B: *whispers to Person C* now we know this guy is not really a fan of the show. Plus it's actually set in the Victorian era.
Person C: I know right! Let's just play along though, for fun.
Downtown-Abbey
A sexual snafu where during climax you accidentally call out Maggie Smith’s name (Professor Mcgonogall from the Harry Potter series)
Man I totally pulled a downtown-abbey last night