Affect. Effect. I can never remember what the difference between them is. This really bugs me, so much so that this week I actually when seeking an answer. I asked Wolfram Alpha; it was able to tell me the population of the town where I live; it was able to tell me how many angels you can fit on the head of a pin, but it was unable to help me with Affect and Effect.
Eventually Grammar Girl helped me out with a picture of an Aardvark. I still felt it was not enough. I found this:
affect is the act
effect is the result
That is the best so far, it is a functional mnemonic, but I feel it lack a certain something. Hannah, where are you? Whenever Ben and I ran into gramatical conubdrums you were always there to help with a handy diagram we could pin up on the notice board.