I saw this game in another forum, and I think it's fun.
You have to change only one letter from a word to form a new one. For example:
User A: TALL
User B: FALL (the F instead of the T)
User C: FAIL (the I instead of the L)
User D: LIAR (the R instead of the F)
... and so on. You don't have to keep the same order of the letters (as User D). The only thing that you have to keep in mind is to change only one letter from the word.
-You cannot (add extra letters to the previous word / delete letters from the previous word).
-If there's no way to form a new word, feel free to say so and write a different word.