How do you manage your SD card library?

txmadman writes: Like a lot of my colleagues and all of my three children, I have several SD and Micro-SD cards for various purposes...cameras, cell phones, my laptop, etc. These things are handy to have around, offer easy and significant storage, but are very easily lost. We have also have run into some instances where it wasn't clear whose SD card was whose, and have also started to see a need for a storage mechanism. I have seen SD card "wallets" and such, but have never seen anyone actually use one. So: How do Slashdotters manage and keep track of their SD cards?