Is it day or night?
Day & Night is an original card game, with a very tricky mechanic.
A classic trick-taking game in which, though, the highest card wins if it is day, and the lowest one if it is night, and the cards themselves determine the change between day and night. A brilliant variation that made this game entering the finalists of Premio Archimede 2016 under the name Tricky days.

Some cards

Day & Night was published thanks to its attendance to Premio Archimede