The demand for certain common cards never ceases to amaze me. Take this 1962 common that recently sold on ebay. Granted it is a mint vintage card and graded by PSA, but wow! The seller did not even list the name of the player or the number of the card in the auction title, and it still went for a nice chunk of change. Make sure to check out the description too, it's good for a laugh.
1962 Topps Common