Take a perfectly useful standardised measurement of length, weight, speed or time, and convert to something far less useful (but much more fun).
Ethan’s ode to the
fr unit in CSS grid.
A nice rundown of some of the fun you can have with viewport units.
Some really great CSS tips from Rich on sizing display text for multiple viewports.
A thorough and compelling demonstration of why it makes sense to size all the properties of your components—font size, margins, borders, etc.—in ems or rems rather than mixing in pixels for some properties. It’s all about the scalability, innit?