I felt this was one of the weaker episodes of the series (that still means it's better than pretty much any other show, but not up to the quality of other episodes). The freak story arc was rather lacking in my eyes (focusing on Milly's temporary involvement with the freaks after her dog's death, and briefly on Nick's attempts to write a song for Lindsay), but the strength of the geek storyline more than made up for it.
The premise behind the freak part of the episode is that Milly's dog has been accidentally run-over by Kim and Lindsay. In consoling Milly for her loss Kim ends up befriending her and Milly deals with her grief by experimenting with the freak way of life: neglecting homework, disobeying her parents, attending concerts, and almost (gasp) drinking a beer. I felt this part of the episode didn't stand up well under pressure. Throughout the series Milly has been the archetype of the good student and straightlaced kid. The premise that she would abandon all of that over the death of a family pet was hard for me to swallow, no matter how beloved the dog was. As I watched the episode I couldn't forget the parallels between Lindsay's and Milly's experiences: Lindsay also fell in with the freaks when her world fell apart after her grandmother's death. Comparing the death of a grandmother to the death of a pet made it hard for me to take Milly's story arc seriously.
At the same time the geek storyline (as always) was exceptionally strong. The episode focuses completely on Bill (instead of Sam) and we end up seeing new sides of his character as he grapples with the concept of his mother dating his gym coach. Martin Starr's performance is phenomenal and masterfully conveys just how much Bill despises Coach Fredricks. The story, dialogue, and performances of Bill, his mother, and Fredricks were so engrossing I didn't even miss having Sam on the screen.
In the end I have mixed feelings about this episode only because of the weakness of the freak storyline. The geek side of the episode is one of the best there is and absolutely worth watching. The scenes of Bill storming away from Fredricks on the verge of breaking down and finally beginning to reconcile with him over an episode of Dallas are a perfect example of the deft blend of powerful drama and genius comedy that make this series so unbelievable.