This led to a smoky trek through a couple casinos trying to find an ATM that worked, until I gave up and took a cash advance on the credit card (much bigger fee, grrrr).
My ATM card has always been very cranky, and I've had to resort to the plastic bag trick mentioned in the NY Times article "Low-Tech Fixes For High-Tech Problems" several times.
So I go to the bank today and try the card in the ATM there. It works. Knowing that only working in the ATM machine at the bank doesn't help me much, I go inside the bank and ask for a new card. I'm already tweaked because I know it takes a week to get a new card and they de-activate your current card then and there.
Well, it turns out my bank has gotten cool. They had a card printer and were able to make me a brand new card right away. Just a couple minutes, and I had a new working card!
Three cheers for my bank! It's nice to know that some of them aren't falling to pieces these days.