In our series My Monday Morning, self-motivated people tell WSJ. how they start off the week. The DJ Marshmello has an unusual trick for curing creative blocks: He forces himself to get really bored.

When COVID-19 hit in 2020, everyone was wearing masks — but celebrity DJ Marshmello was ahead of the trend way back in 2015. Even those who don’t know Marshmello by name likely know of a few of his ...