Leather (mine is Bison leather from the farmer's market)
Scissors
Hammer and nail (or awl - something to poke holes in the leather)
Crappy cutting board or wood scrap. (don't use a cutting board you'll want to use again because the holes you'll make in it will make it difficult to clean)
Dental Floss (to sew leather - it's minty fresh!)
Velcro (or some other fastener to keep it closed)
Thread (to attach the velcro)
Something to mark the leather (I used a black marker, which does not come off)
Optional: a patch to sew on opposite the velcro.