John's Links

Citizens worldwide can now help identify newly formed black holes, contributing to groundbreaking astronomical research.

A color naming test designed to measure your personal blue-green boundary.

You might have some luck with this service if you leave something behind in a hotel.

Read some advice, leave some advice. But you can only visit the site once.

Details some of the fun shenanigans that went on during the time that One Million Checkboxes was live.

Or you can watch the author tell the story.