Hi,
If you ever want to see a bit that is absolutely how/what Peter Sellers was as an actor, you must see "Being There" and make sure you catch the bit during and after the credits! If you don't you want appreciate what a great actor he was.
I have over 120 Goon Shows, which is where Peter got his start, and his voice changes are down right unreal and fantastic, and he shows that mentality and continuity in his film work, time and again.
Lots of folks think that Inspector Closeau is great, but nope ... the better characters are Major Dennis Gritpype, and of course ... Blue Bottle! ... well, Henry Crun is cool too ... ohh wait ... and if you never heard those over and over for 12 years, you have no idea what "acting" is all about, and why he could do Closeau 100 times over, and always be funny!
And we haven't even started talking about Dr. Strangelove, where he does a total of 6 different characters ... see if you can point them out ... hint ... some are not visible!