Jeffing is a traditional gambling game played by printers, using movable type as dice. In particular, the em quad (a piece of type without a letter, used to introduce a space of em width) was used as it approximated a cube and had a nick in one face (to indicate the front of the piece of type).
Players cast five or seven em quads on a flat surface and count the number of nicks showing on the tops of the quads. All players agree on a stake. Players than cast the em quads the same number of times and the highest scoring player wins the stake. The remaining players then cast the quads again and the lowest scoring player has to pay the highest scoring player the stake.
This description is based on a description from the early 19th century, an excerpt of which can be read here: http://www.poormojo.org/pmjadaily/archives/026778.php