A couple of Ogden Nash's finest:

Little gamboling lamb
Do you know where you am?
In a patch of mint
I'll give you a hint
Scram, lamb.

When called by a panther
Don't anther

But what bugs me is when people use the indicative pronoun "I" in the objective, for the sake of a rhyme:

From "Aragon Mill," an otherwise fine song:

I'm too old to change and I'm too young to die
There's no place to go for my true love and I

Particularly when there's a perfectly good option:

We've no place to go, my true love and I

Charles