Here are two poems in honor of pi, from the Mathematical Poetry site:
If inside a circle a line
Hits the center and goes spine to spine
And the line’s length is “d,”
The circumference will be
d times 3 point 1 4 1 5 9.
Simple Simon met a pi man
Going to the fair.
Said Simple Simon to the pi man,
“You have unusual ware.
The pie’s I’ve seen before were round
But, gosh, your pi’s r2.”