What's that, exactly?
Well, we've all heard scores of funny songs, meaning with humorous lyrics, but how often have we seen, or rather heard, comedians using the music itself, never mind the lyrics, to funny purposes?
First name that comes to mind to me has to be Dudley Moore, he was an amazing musician, both on the serious and the funny side of it, his renditions of "Colonel Bogey" and "Delilah" in the style of Beethoven, and it WAS Beethoven, are wonderful pieces of arrangement in themself, but they crack you up as well, and he did many of that sort, mostly sadly lost...
And then... is it Bill Bailey? Yes, it is... first time I've seen one of his musical numbers I was blown over, it was the Belgian Jazz-style rendition of the Doctor Who's theme, I guess (Le Docteur Qui

), and saying he's a skilled musician is almost reductive... and then there's Cockney music...

One of the best live shows I've seen in the past few years has to be "Bill Bailey's Remarkable Guide to the Orchestra", in which he in fact did quite a few old numbers, but if you've never heard a symphonic orchestra going "Have a Banana!", you can't really understand what music is all about...

Apart from them two, though, I can't think of many comedians using music that way, Lee Evans perhaps, who's a quite impressive drummer and percussionist, but I don't know him well (yet).
Oh, and I recently discovered Norman Wisdom was an excellent drummer himself, among his many acrobatic talents, but I don't know how much he used that, not much in movies...
And then there's Billy Connolly and his banjo... but, as he says himself, it's always the guitar player that gets the girls, and the banjo player is left behind, going "plonk, plonk"...
