Five card draw is one of the most common types of poker hands. Each player is dealt five cards, then a round of betting follows. Then each player may discard up to 3 cards (4 if your last card is an ace or wild card, in some circles) and get back (from the deck) as many cards as he/she discarded.
In 5-card draw, the standard hand rankings are (from highest to lowest): Royal Flush, Straight Flush, Four of a Kind, Full House, Flush, Straight, Three of a Kind, Two Pair, One Pair, High Card.