Another device to remember pi is the footbal-cheer used at various schools of engineering. The variant I learned is from Rensselaer Polytechnic Institute:

e to the X dy/dx,
e to the X dx,
cosine, secant, tangent, sine,
3.14159,
square root, cube root, log of pi,
dis - integrate them RPI!

an aside:
(1) the first two lines allude to the famous and onomatopoeic Croaking Chorus from Aristophanes' comedy, The Frogs: "Brek-kek-kek-kax, co-ax, co-ax. (2) cross-threading: that chorus is also the answer to a poser I posed a few weeks ago: what is a "caxi"?