You might forget where you left your keys or your glasses, but some things are forever imprinted in your memory one way or another. And for those things you simply can’t seem to remember, some useful mnemonic devices can help you. For example, how can you remember the presidents on our bills? And what about all the spelling rules our language has? Is it "gray" or "grey"? Don’t worry, we’ve got you covered. Keep reading and learn a few tricks.