Nice link from Citizen Chris with the CoolStandings odds on the post-season to this point in the season. I noticed this towards the end of last season on ESPN's standings page, but I didn't realize they would do it this early.
Anyhow, good news, I guess. The Astros have a 7.1% better chance of going to the playoffs than they did in 2005! In the Top Comebacks section our Houston Astros on June 7, 2005 had a 0.2% chance of making the playoffs. Of course they went to the World Series, where they had a 50% chance of winning, and got smoked.
This is an interesting site, as the Red Sox and Yankees have the same record, at 9-6, yet the Red Sox are given a 51% chance of making the postseason while those Yankees sit at 20.7%. As of today the Astros are given a 3.5% chance of winning the NL Central, a 3.8% chance of winning the Wild Card. Add that up, and there's your 7.3% chance of making the playoffs.
How do they do it? I'll just let you read it.