Below is the Pythagorean table for the 2010-11 French Ligue 1 at just past the halfway mark of the season (matches played up to 15 January). The league Pythagorean exponent is 1.70.
When I was taking a look at the goal distributions for each of the teams, I was half-expecting Rennes to be the big overachiever in the league, or at least among the top four sides, because of their defensive record. (Recall a previous post in which I noted that consistent defense is more likely to predict league winners.) But in fact the top four are playing roughly in line with their expectations, and I think the reason Rennes isn't performing any better is because their goalscoring hasn't kept pace with PSG or Lille. It's not that they're performing badly, it's that if they had a consistent goalscorer they might be in second or even first (Rennes' leading scorer has four goals!).
No one else in the league is strongly outperforming expectations — perhaps Montpellier and Nancy are, but they're wriggling their way out of the relegation zone — but Monaco and Sochaux have clearly underachieved at this stage of the season. Sochaux have scored 30 goals — third highest in the league — but lie in tenth place. Ouch.