Wikipedia
Fāl-gūsh
Fāl-gūsh or fāl-gōsh is the act of standing in a dark corner spot or behind a fence and listening to the conversations of passersby and trying to interpret their statements or the subject of their dialogue as an answer to one's questions. It is a traditional Iranian custom that certain days are especially good for divination. During the last Wednesday of the year, the Chahārshanbe Suri; divination, especially by listening to the conversations of the passers by and interpreting that which is heard (fālgūsh) as a sign is quite common. Fortunetellers, (fālgīr), who are mostly gypsies, are still active in some parts of Iran.