This is a poker term used to describe a Texas Hold-Em starting hand that consists of two cards both with a rank of five, also called "pocket fives". This nickname comes from the Usenet newsgroup rec.gambling (now rec.gambling.poker), and is sometimes used among the readership of that newsgroup to identify other members when they are playing at casinos. The standing joke is that the hand must be played as if it were the absolute best hand and if it wins the pot then you must shout out "PRESTO!". This is derived from the magician's phrase used when completing a magical trick.