Perhaps I should explain the origin of the 'Mondegreen' for those who may not know. In the Scottish ballad 'The Bonny Earl of Murray' there's a line which states 'They lay'd him on the green' which was misheard as 'Lady Mondegreen'. The Mondegreen was born.
I've always liked Jane Asher's personal example. She received a letter addressed to Mr J Nasher, which opened Dear Mr Nasher. She rather liked it, so never told the Company of their mistake.
There is the popular school hymn which most children sing as 'Gladly my cross-eyed Bear'.
The tune 'A Merry Conceit' was often referred to as 'American Seat'.
A Scottish 'County surveyor' was once referred to as The Countess of Ayr'.
There is a story of a typist's copy being checked only to find that instead of 'juxtaposition' she had typed 'Jockstrap position'.
Imagine receiving an invitation to a 'Haddock-Stirring Committee' when you expected to have been invited to an 'ad-hoc steering committee'.
And finally I did hear that someone once called Directory Enquiries to find the phone number of London's famous 'Wig and Pen Club', only to be told that there was no Pen Club in Wigan.
I'm sure you have your favourites, so let's hear a few more (not from songs please)!