I don't know anyone who has ever run out of their initial supply of business cards. I assume it takes a special kind of douche to force them upon strangers so frequently that you'd need to reload.
One inconsequential line of my signature block changed a few weeks ago, so new business cards were printed for everyone in the area. I looked at the box of my old cards, and considered the staggering amount of similar paper waste that goes on every day in businesses across the globe, and I wondered how these old cards could be meaningfully re-purposed.
As a youth, I'd build multi-story complexes from playing cards, and then shoot rubber bands at them until they crumbled. (It's hard to say why I chose to do this; either we didn't have Nintendo yet, or my sibling was playing a marathon Dragon Warrior session.)
I knew just one well-placed rubber band would collapse this structure, so I instead chose to see how long it would survive on my desk.
A few hours later, a young woman walked into the cube and intentionally fanned her notebook toward the pyramid.
HER: "I didn't think it would fall down!"
ME: "It's a HOUSE of CARDS!"
HER: "I thought you taped them together."