Six-sided dice (d6) are used for many things in Dungeons and Dragons. In fact, they're probably the first dice a new D&D player will roll when they're creating their first character. d6 are used to determine a character's basic stats: strength, dexterity, intelligence, wisdom, constitution and charisma.

One DM I play with says "Ok boys, bring lots of d6's" when he thinks he's going to wipe us all out -- usually we disappoint him!