Spook, Ghost, and other variants
The game of Spook is a derivative from Ghost, so I shall explain Ghost (the
simplest of the variants) first.
The players take it in turns to add a letter to the end of a word.
The letter mustn't complete a word (words three letters or less don't count).
The letters must still be able to become a word on a subsequent turn.
If a player whose turn it is believes the last letter played was invalid
(it completed a word, or doesn't lead to a word) they say "challenge". If the
challenged player can show their play to be valid (give a word that the letters
could lead to, and/or show that the letters so far don't make a word),
the challenger gets a bad-point. If the challenged player did, in fact, make
a mistake, or was bluffing, the challenged player gets a bad-point. The next
round begins with no letters again, from the next player.
The bad-points represent letters, hence the name of the game... A player
with one point is a 'G', two is a 'GH', and so on until with five they're a 'GHOST'.
Once a 'GHOST', the player is out. The last player to remain is the winner.
Example round of Ghost:
Bob : P
Tim : PO
Bob : POL
Tim : POLI
Bob : POLIT
Tim : POLITI
Bob : POLITIC (thinking of POLITICS)
Tim considers challenging, suspecting that POLITIC is a word. After a moment's
thought he realises there is a safer idea, as he isn't sure.
Tim : POLITICA (for POLITICAL)
Bob realises he's flummoxed. On the offchance that Tim might be stupid, he
tries
Bob : POLITICAT (hoping to mislead Tim into going for POLITICATION)
Tim : Challenge - not a word.
Bob admits it, and becomes a 'G'.
The second variant of the game is unnamed - in this variant, letters can
be added to either end of the word, rather than just the back.
Example round of (unnamed):
Bob : P
Tim : AP
Bob : APT (three letter word doesn't count)
Tim : RAPT (thinking of RAPTOR)
Bob : Challenge - RAPT is a word.
Tim : Doh! (slaps his forehead and becomes a 'G' (we still go for ghost, since the game isn't named))
Finally, my preferred variant, Spook. In this, letters can be added anywhere
in the word.
Example round of Spook:
Bob : X
Tim : XT (thinking of 'EXIST', 'EXCITE' etc.)
Bob : JXT
Tim ponders for a bit.
Tim : Challenge - not a word.
Bob : JUXTAPOSE
Tim : Doh! (slaps his forehead and becomes an 'S' (first letter of 'spook'))