In 1970, Parker Brothers published Smess: The Ninny's Chess. The colorful board, goofy pieces, and crazy names marketed the game toward kids (under the assumption, maybe, that no kid in his/her right mind would want to play a serious chess variant?) Unfortunately, Smess was (or could be) a serious game.
Then in 1979 (maybe recognizing it had a serious game on its hands?), the game company rethemed Smess and retitled it All the King's Men, now with a nicer adultish board and Medieval-style pieces. Unfortunately, during the repackaging process they left out a key rule: promotion !
They probably left out promotion by accident (I hope anyway), but in any case this essentially wrecked the game, turning it into a drawfest. So if you do manage to find a copy of All the King's Men (now out of print), make sure you reinstate promotion.
Direction of movement in the game is not determined by the type of piece, but by the square a piece rests on at the beginning of a turn...just follow the arrows. This is the key defining feature of All the King's Men, and for hardened chess players it can really (s)mess with their minds. Other than that, kings and archers move a single square and knights move any number of squares without jumping. The object is to capture the opposing king.
You can play Smess either real-time or turn-based at play.chessvariants.org.
For complete rules (warning: this is a link to a .pdf file), click here: Smess