This brilliant fanpost by Traco Bucco at Bucs Dugout chronicles the 35 most memorable games between the Pirates and Astros in 51 years together in the National League. With the Pirates' last series against Houston now over (it was a pathetic matchup between a terrible team, and a mediocre team that has seemed terrible), the Bucs watch the Astros depart for the American League.
Astros vs. Pirates probably doesn't top most fans' lists of classic rivalries, but the two teams have played a ton of interesting games. The big one for me, as a younger guy, was a July 2001 matchup that featured a wildly improbable come-from-behind victory:
In the middle of an otherwise dreadful day-night doubleheader (the nightcap was a 12-3 rout at the hands of future Buccos Tony McKnight, Ron Villone, and Octavio Dotel), the Pirates shocked the Astros by rallying for seven runs with two outs in the bottom of the ninth inning to win the opener 9-8. Much-maligned Pat Meares ignited the rally with a two-run homer off Michael Jackson; Brian Giles (who earlier in the game had denied Vinny Castilla a four-homer game with a catch at the left-field wall) concluded it with a grand slam off lefty closer Billy Wagner.
The Pirates finished the season with a 12-5 record against the Astros, so the Bucs will miss Houston, and not just for nostalgic reasons. The Astros should be pretty bad for the next couple seasons, and the Pirates will have to make up for all those wins elsewhere. Eventually, though, the Astros will probably come back to life -- they can support a healthy payroll, and they have a new GM, Jeff Luhnow, who seems to know what he's doing. When they wake up, they'll be an American League team, and in the final analysis, the Pirates will probably be pretty happy that the Astros are gone and that the NL Central only has five teams.