Milo handed over a faraway boring Tuesday. The librarian stamped his card "PAID" in gold. "Smart choice," she said. "You kept your good days and spent a dull one." Milo walked home grinning. Weeks later, one Tuesday simply didn't happen for him, and he never even missed it.

Milo gave back the rest of today instead. The world went gray and still, like someone hit pause. When color came back, it was sunset again and the evening was gone. But his science fair trophy still sat on the shelf. "You kept the prize and paid with your evening," the librarian said. Milo decided that was fair.