The players were divided into 2 teams. When it was team A's turn, there would be 2 givers and 1 receiver from team A, but the word
would be chosen by a member of team B who would provide every third word. After the number of players dwindled, play just shifted
around the table, with one receiver, and 2 good givers plus one saboteur who chose the word. The receiver knew who the saboteur was,
but the constraint of forming a grammatically correct sentence could throw off the 2 good-guy givers pretty badly. Fortunately the
sentences did not also have to make sense.
This game is described in Tyger's 1998 con report and
credited to Al Desuda.