Learn a Piem... that's a great way to memorise Pi.

http://cadaeic.net/naraven.htm

The number of letters in each word represents a digit of pi. Ten represents zero, and eleven represents two one's one after the other. The example above allows you to learn Pi up to 740 digits, and there are more verses for later, if you're interested. If you're good at learning poetry you could get up to near 4000 if you wanted. (I'm not there yet!)