7-Card Stud (or just "Stud" for short) was one of the most popular variations of poker, prior to the advent of Texas Hold'em and Omaha. Stud is almost always played in Limit format. It differs from Texas Hold'em in the following ways:
Each player is initially dealt two hole cards face down plus one card face up. The up card, known as the door card or 3rd street determines who acts first. Ties are broken by suit, alphabetically, in the order of clubs, diamonds, hearts, and spades. So the deuce of clubs is the lowest card and the ace of spades is the highest. The player with the lowest card acts first and is not allowed to check or fold. His two options are to either bet the "Bring In" amount (which is typically more than the ante but less than the small bet) or make full bet in the small bet amount. Play then moves clockwise where the next players have the option to fold, call, or raise using the same rules are Limit Hold'em.
After all bets are in (and at least 2 players remain in the hand), one new card (4th street) is dealt face up to each player remaining. From this point one, the player that acts first is determined by who has the best hand showing face up. Also there are no more bring-ins for the remainder of the hand so the first player can check his option if he wants to. Otherwise he can bet in the small bet amount. There is one exception, however. If any player is showing a face up pair (i.e., his 3rd and 4th street cards have the same rank), then any player can start making bets and raises in the Big Bet amount. Once that is done, the betting in the remainder of the round will be in Big Bet amounts.
After all bets are in, one new card (5th street) is dealt face up to each player remaining. From this point one, all bets and raises are in the Big Bet amount.
6th Street is also a face up card and the betting round works the same as 5th Street.
The 7th and final (River or 7th Street) card is dealt face down. With one exception. If enough players remain in the hand then there might not be enough cards left to deal one to each player since the deck has 52 cards and 8 players getting 7 cards each would total 56. In that case, a single community card is dealt face up on the table for all players to use. Other than that the betting round proceeds as it did for 6th Street. If there is more than one player remaining a showdown occurs with players turning their down cards up and the one with the best 5-card poker hand wins. Splits and side pots work the same as they do in Hold'em and Omaha.
Stud Hi-Lo (also referred to as "Stud 8 or Better") is a variation of 7-Card Stud where the pot is split by the players with the best high hand and the best low hand. The same player can win both halves of the pot. The high hand is determined in the same way as regular Stud described above. The low hand is determined by the player who has five unpaired cards of the lowest rank, using any five of his seven cards. These do not have to be the same five cards used to make the high hand. Aces count as low cards and none of the five cards can be higher than an 8. Straights and flushes are not a factor in calculating the low hand so the best low hand is 5432A while the worst is 87654. Any combination containing a pair or a 9, 10, J, Q, or K is not qualified for a low hand so not every hand will have a qualified low hand. If there are no qualified low hands at showdown, the player with the best high hand wins the whole pot. If the pot contains an odd number of chips and there is at least one qualifed low hand, the extra chip is awarded to the high hand. Both the high and low halves of the pot can be split by multiple players in the case of ties.