If I may be permitted a bit of self-promotion, here is my contribution:

There once was a SAS book called "little"
That really was more in the middle
Too big for a poem
Too small for a tome
Made it just right for solving code riddles!

Also, I'm pretty sure that Lora Delwiche and I are the only SAS Press authors who ever wrote a poem for our books. It's not a limerick, but we included this homage to our editor, Stephenie Joyner, in the Acknowledgements section of our books for SAS Enterprise Guide 3.0 and 4.1:

And now to our editor,
we specially credit her
patience and humor.
They're not just a rumor.

With Box 1 and Box 2,
our inquiries flew
with Pane 3 and Pane 4,
and windows galore.

From technical questions
to note box suggestions
she knew what to do
and she guided us through.

Happy National Limerick Day to everyone at SAS Press!
Susan