I always love buying second hand memory cards as you never know what you might find on them. I bought a couple earlier today and while there wasn't any long lost dlc on them, there were quite a few saves on there from Sonic adventure, jet set radio etc. The memory card without the screen has the Chao game on it which is funny seeing as you can't actually play it without a screen!
What are your best second hand memory card moments? My best has to be when I bought a ps2 memory card with a 007 Nightfire save called "WET SLAG"