Little tiny photo cards can carry a lot of data. I have a 16 Gb micro SD card in my Android phone. But what if you need to deliver a micro card surreptitiously? They're tiny - you can lose in your pocket.
Spy gear to the rescue. I came across this great site, selling hollow coins for secretly transporting data. Take a look at this:
Only $30! I wonder if I will ever need one of these. Even if I don't, it's kind of cool.