One card to rule them all
If you're like me, you have a ton of those little VIP Frequent Shopper Should Be Discounted All the Time But Isn't cards. I hate that they exist; why should I have to give you a computer database of my shopping habits in order to get the lowest prices? I try to mess them up by letting the person ahead of me borrow my card when they obviously don't have one; that way, my database has denture cream, dog food and baby food in it, even though I never buy those items.
Well, apparently someone else is tired of carrying around a dozen different cards, and they've come up with a way to put all of your cards onto one card.
"This is a simple web application I made. The goal is to fix the problem of having to carry around tens of loyalty, discount, and club cards every time I go shopping. I finally broke down and created this page when I realized my wallet was way too thick and 3/4 of the thickness was from the various supermarket and other loyalty cards."
I don't know how many stores would accept this, but it might be worth a shot. Of course, if you're like me, you refuse to carry the card and just make the cashier punch in your phone number every time.