This is the easiest craft ever!
I needed some extra magnets, so I took out my box of bottlecaps (I bought these on eBay a couple of years ago when I did a resin-poured bottlecap project):
…got my hot-glue gun, and some magnets out:
Put a dot of hot glue on the back of each bottlecap:
…carefully put the magnet on:
…and they were all set!
I make bottlecap thumbtacks for Av’s office, too. All it takes is the hot-glue gun, bottlecaps, and quilter’s thumbtacks: