Eight. Four teams make the playoffs in each league. There are three divisions in each league and the three teams that wind up in first place in their division make the playoffs. The fourth team to make the playoffs is the team that did not win their division but has the best overall record of all the teams that did not win their division. That team is called the "wildcard" team.
In 1993, the baseball teams that made it to the Major League Baseball Postseason were the Toronto Blue Jays, the Chicago White Sox, the Philadelphia Phillies and the Atlanta Braves. The Blue Jays beat the White Sox in the Championship Series in 6 games and the Phillies beat the Braves in 6 games in the Championship series. In the World Series, the Blue Jays defeated the Phillies in 6 games.
NL: Phillies, LA Dodgers, Cardinals, Rockies
AL: Yankees, Red Sox, Angels, and whoever wins the Twins/Tigers playoff game
Red Sox Philies
As of 2012's Postseason, 10 teams in total, 5 teams from each league will make the Postseason.
With the Tampa Bay Rays making the playoffs in the 2008 season, all MLB teams have made the playoffs at least one time.
Houston Texans has never made the NFL Playoffs.
One club that has not has not played in the World Series is the Seattle Mariners.
What NBA teams made the playoffs with more loses than wins
Teams that have started 1-4 and made the playoffs and won their division: 1992 San Diego Chargers, 1993 Houston Oilers, 2002 Tennessee Titans, 2002 New York Jets and 2004 Green Bay Packers.
Now that Tampa has made the playoffs, every single MLB team has made the playoffs at some point in its history, although Washington hasn't made the playoffs since they moved to DC; their last playoff appearance was in 1981 as the Montreal Expos.
Yes the NHL playoffs are fair. The top 8 teams in each conference make it to the playoffs. It doesn't matter what team your own, it just matters if you made the top 8 teams. The playoffs are completely fair.
The bad ones?
The bad ones?