An ELI5 of the ethereum parity incident:
"A guy named Gav convinced people put all their money into a box. But none of them knew that the box would burn down if you just tossed it around enough. Then your 2-year-old little brother found the box. So the box burned down, all the money is gone and people are very very mad at Gav and your 2-year-old brother. They are also trying to figure out how to go to a parallel universe where all of this is just a nightmare and never really happened."