Jotto is a two player game, whereby each person picks a 5 letter word and they would try to guess the other person's word before theirs is guessed. You would first guess some other five letter word, and your opponent would tell you how many letters his hidden word had in common with the one you just gave. This is a very interesting game as it involves a high degree of logic an inference, but a good supply of 5 letter word is of infinite usefulness. There are but a few limits on the choosing of your hidden word: it must be English (or whatever language you may decide upon); it must not have an anagram; and it must have 5 unique letters. Those who have mastered both logic and the English language (or at least the 5 letter words that comprise it) may solve a game in 5 turns, but those without such skills and talents may go on endlessly with no hope of ever solving it.
This is an interesting get-to-know-you game, too, for rainy days. The words you use my say a lot about you. One whose words are

study
learn and
teach

may just be incompatible with someone who chooses
lick
fuck and
bite. (I know they're not 5 letter words, that was part of my dry sense of humor.)