To the finals, once.
Since their inception in 1974 til 2009, the Washington Capitals have qualified for the Stanley Cup playoffs, 20 times including 14 straight seasons from 1982-1995. They have appeared in the Stanley Cup Finals once, losing to the Detroit Red Wings, 4 games to 0 during the 1997-98 season.
In the ABA, they made it to the playoffs 7 times. In the NBA, they made it to the playoffs 16 times.
They have made the playoffs 25 times with a record of 17-18.
Since the Dallas Mavericks were established in 1980, they have made it to the playoffs 20 times.
15 times
Through the 2013 season, the New York Giants made it to the playoffs 31 times.
Since moving to Tennessee they have made the playoffs six times - 1999, 2000, 2002, 2003, 2007, and 2008. Their record in the playoffs is 5-6.
Through the 2012 season, the San Diego Chargers made the playoffs 17 times.
The Chicago Bulls have made the playoffs 29 out of their 44 seasons.
27 times
twice
26