Robert Murray-Smith posted a new video (with unsynchronized audio) showing how to make graphene-oxide at home. The basic idea is to start with a mix of sulfuric acid and phosphoric acid, add powdered graphite and stir it. Then you add permanganate and stir it for three days. Robert hasn't managed to actually isolate the graphene oxide, but he's working on that:

If anyone tries that himself, let us know the results...