The reading for this word is a complete exception, though the word itself is incredibly common and useful. When you think of "today" think about what you have to do today for work.
You have to work in one of those mall kiosks (きょう). Just think about how sad you are that you have to do this today. What a crummy day. It's sunny outside and you're stuck in a mall manning this hermit crab kiosk.
Note: This reading mnemonic is pretty far away from the actual reading, as far as reading mnemonics go. Use this to get yourself close, and then use your own brain grapes to get the rest of the way there. This one won't be as easy as most of the others, but do some good old fashioned memorization and you should be okay. I won't ask you to do this much, fortunately. :)
Today’s homework is question two on page twenty-one.
Today's sales are less than usual.
Oh, was today my birthday?