Exactly. I had heard the sketch a few times before hearing it performed by Abbot and Costello, and I still found it hilarious. Timing really is everything.
While we're at Shakespeare-izing modern comedies, I present a link to "Two Gentlemen of Lebowski". Yes, it's exactly what you think it is. It's five acts long.
http://www.runleiarun.com/lebowski/
I thought this was a fairly good presentation of Who's On First. Timing truly is everything in a piece like this.