I'm 51 years old and have a vivid memory of all of the 10 Penguins-Capitals playoff series. Here's a synopsis:
1991: 2nd round - Pens in 5
This was the first Stanley Cup year for the Penguins, and they made quick work of the Capitals. The Caps won the first game 4-2.... and were up 6-5 in game #2 with under 5 minutes to play after being down 5-3 at the second intermission. The Caps replaced goalie Don Beaupre before the 3rd with Mike Liut. They then stormed back with 3 unanswered goals to take the lead. Randy Gilhen of the Pens scored his first ever playoff goal with 4:35 remaining in the 3rd to tie the game at 6... and Kevin Stevens scored 8:10 into OT. The Pens then easily won games 3 and 4 in DC and then game 5 in PGH on their way to their first Cup.
1992: 2nd round - Pens in 7
The Capitals took a 3-1 series lead with a blowout win in Pittsburgh in game #4, 7-2. At this point, Mario Lemieux conducted a players-only meeting in which the Pens decided they would switch to go to a "1-4 delay" system - a precursor of the "left-wing lock". The idea was to slow down the Caps offense that had scored 20 goals in the first 4 games and rely on the Pens counter-attack and powerplay to score goals. The Pens went on to win the next 3 games to win the series on the way to their second Cup.
1994: 1st round - Caps in 6
This was the only year in which the Caps defeated the Pens in a playoff series. The Pens were the #2 seed in the conference and the Caps were the #7 seed, so this was a huge upset. The eventual Cup winner Rangers made easy work of the Caps in the 2nd round.
1995: 1st round - Pens in 7
For the second time in the rivalry, the Caps had built up a 3-1 series lead, again scoring 20 goals in the first 4 games. In a critical game 5, the Caps took 2-0, 3-2, 4-3, and 5-4 leads before the Pens' Kevin Stevens scored to tie the game at 5 and force overtime. Luc Robitaille scored in OT to win the game for the Pens, and the Pens then went onto win games #6 and #7 by scores of 7-1 and 3-0 as Ken Wregget was outstanding. Eventual Cup winner New Jersey beat the Pens in 5 games in the next round.
1996: 1st round - Pens in 6
The most memorable game in this series was game #4 in DC, with Washington leading the series 2-1. This 4-OT thriller became known in Pittsburgh as the "pajama game".... it didn't end until almost 2:30am Eastern Time and it featured the Pens wearing their new "alternate uniforms" that looked like Pens PJs. At the time, it was the 2nd-longest game in NHL history. Petr Nedved scored with just 45 seconds left in the 4th OT to win the game. Tom Barrasso and Ken Wregget combined to make 61 saves (53 by Wregget) and Olag Kolzig of the caps made 62 saves. The game featured a penalty shot in the second OT by Peter Bondra, but was saved by Wregget. After the OT win, the Pens won games #5 and #6. The Pens eventually ended up losing in game 7 to the Florida Panthers in the conference finals.
2000: 1st round - Pens in 5
The 7th-seeded Pens dispatched the 2nd-seeded Caps in a series that was more difficult than the 5 game victory would make it seem. The Pens won 7-0 in game 1... but the next 4 games were all 1-goal games, with the Pens winning game #2 in OT 2-1, game #3 4-3, and game #5 2-1. Game 4 was a Caps win, 3-2. The Lemieux-less Pens were dispatched by the Flyers in 6 games in the second round.
2001: 1st round - Pens in 6
The return of Mario Lemieux to the playoffs was the story of this season. Lemieux scored 4 goals in the series and the series featured five 1-goal games. The Penguins would eventually lose in the Eastern conference finals to the Devils in 5 games. This season would be the last time that Mario Lemieux ever participated in the playoffs.
2009: 2nd round - Pens in 7
This was the first Crosby-Ovechkin matchup in the playoffs, and the first time the Pens and Caps had met in the playoffs in 8 years. 5 of the 7 games were 1 goal games, and 3 of the games went to OT. The only blowout game was game #7 in DC, in which the Pens won 6-2.
2016: 2nd round - Pens in 6
Five of the six games were decided by 1 goal... including 3 in OT... as the Pens won again against the Caps on the way to their 4th Cup. Sidney Crosby scored 0 goals in the series and Ovechkin scored just 2. The stars of the series were the Penguins HBK line (Hagelin, Bonino, Kessel) who scored 7 of the Pens' 16 goals and young rookie goalie Matt Murray who repeatedly stoned the Caps.
2017: 2nd round - Pens in 7
The Capitals stormed back from a 3-1 series deficit to force a 7th game on home ice. But Marc-Andre Fleury shutout the Caps 2-0 in game seven for the Pens to win yet again on the way to their 5th Cup. The Pens won games 1 and 2 in DC... but the game of the series was the Caps' OT win in game 3 in Pittsburgh. The Caps had a 2-0 lead late in the 3rd period, and the Pens scored two goals in the final two minutes with the goalie pulled to force OT. Kevin Shattenkirk's OT goal saved the Capitals from a colossal loss.