Matt Groening, the creator of the Simpsons, did a good one of the Pledge of Allegiance in his comic Life in Hell - I read it years ago. I'm sure the Pledge of Allegiance has been done a million times, but it's pretty funny nonetheless...

"I plead alignment to the flakes
of the united snakes of a merry cow
and the Republicans for which they scam
One nacho, underpants..."

and so on. I can't remember the rest. However, since I'm Canadian, I don't know the real text to the Pledge, and Groening's version is the only thing that comes to mind when I hear the Pledge of Allegiance!

On another American note - Ramona Quimby, a character in children's books, learned the Star Spangled Banner as "Oh say can you see, by the donzer lee light" and she was convinced that a "donzer" was a type of lamp, which gave off a "lee" light (she figured it somehow described the type of light). Pretty good. However, that bit didn't make much sense to me when I was about nine because I had never even heard the Star Spangled Banner at that time.