Playing marbles is a classic game that has been around for centuries. It involves shooting and knocking out other marbles with one's own marble. The term 'playing marbles' can refer to a variety of different types of marbles, including steelies (8 letters), MIBS (4 letters), AGATES (6 letters), immies (6 letters), taws (4 letters), and catseyes (8 letters). Steelies are made of steel and are the heaviest type of marble. MIBS are small and usually made of clay. AGATES are made of quartz and come in a variety of colors. Immies are made of glass and are the most common type of marble. Taws are larger than MIBS and are usually made of clay. Catseyes are made of glass and have a unique pattern inside.