Odd Items in Your Wallet?

A commenter mentioned an interesting item for your wallet: glasses. The typical pair of glasses will require a full size case such as this Louis Vuitton Glasses Wallet Case. But if you want to fit your glasses into a typical wallet, it's going to require a special pair of glasses (credit Uneasy Silence).

What useful and interesting items do you carry in your wallet? One slightly unusual thing I carry is floss in a single-use wrapper. I have never had a chance to use it, but I suppose it may come in handy one of these days. At least it's small and light.