One of my favorites.. :
There was a young man from Nantuckett
Who ... waitaminit.... oooooops wrong one...
E = MC2
by Morris Bishop
What was our trust, we trust not;
What was our faith, we doubt;
Whether we must or must not,
We may debate about.
The soul, perhaps is a gust of gas,
And wrong is a form of right;
But we know that Energy equals Mass
by the Square of the Speed of Light!
What we have known, we know not;
What we have proved, abjure;
Life is a tangled bowknot,
But one thing is still sure.
Come little lad; come little lass;
Your docile creed recite:
"We know that Energy equals Mass
by the Square of the Speed of Light!"