Mixing it up on Halloween

The next day was Halloween. Jon just couldn't let the night of fright go by without using the stone. He knew Karen would be piss but thought of fun on Halloween was too much for him. Jon considered all kinds of ideas - pranks on his neighbors, ghosts chasing trick-or-treaters... However, Jon thought to himself "What fun is it if I know what's going on?" So Jon grabbed the stone and said "I wish something...unusual...and unpredictable happens this Halloween night, and that I for the next 48 hours I do not remember this wish or the stone"