Fun things to do with old business cards

I now have quite a collection of old business cards from former employers, and I’ve been thinking about what to do with them. Sure, I could trash them (after I save a couple), but that’s just a waste.
I’m putting together a list of things to do with them.
So far, I have:
note cards
replacement shingles for the roof (temporary at best though)
My wife even suggested making a dress out of them (but I don’t think I could pull that off 😉 ).
Anyone else?