Deliberate "mistake": Lindsay is not at Caleb's funeral in the last episode of season 2, "The Dearly Beloved". It's unlikely that she would have missed it - she is still on good terms with him and he is her father, the only reason she left was to be with her mother, not because she didn't love Caleb.Obviously they didn't want to create another drama with having Lindsay there while they had to focus on the important story-lines - Caleb's death, Kirsten's drinking and Marissa shooting Trey.

Continuity: Season 4 - Episode 8 - The Earth Girls Are Easy - When Kaitlin is at the party, talking to Bullit, her strand of hair changes from hanging over her eye to hanging down next to it, without her moving her hands or head to displace it.

Continuity: In season two, episode "The Return of the Nana", Marissa's arms change position repeatedly while she and Trey are down at the beach. Also, her bag appears with her, even though she left the apartment without it.

Continuity: In season 2 episode "The Risky Business", the top Summer holds changes position in her hands.

Continuity: At the beginning of the second episode of season 3, "The Shape of Things to Come," Summer, Marissa, Ryan and Seth are ordering pancakes at the restaurant. In this whole scene, Marissa's blue mug keeps changing position between shots.

Continuity: At the beginning of the first episode of Season 3, "The Aftermath", Ryan's hair is much shorter than it was at the last episode of season 2. Since they arrive at the hospital with a bleeding Trey, we know that this is right after Trey got shot. It doesnt make any sense that Ryan would go get a haircut right after Trey got shot and then go to the hospital with him.

Continuity: Season 4 Episode 5 The Sleeping Beauty: When Taylor calls Ryan in the middle of the night (around 03:03 when he first checks), the second time Ryan checks the time on his radio it shows 03:23, however it jumps back to 03:04 when he looks again.