#1: Brooke and Lucas' Pregnancy Scare
#2: Dan's Heart Attack
#3: Lucas and Keith Moving to Charleston
#4: I forgot how early Nathan and Haley got married
#5: Sheryl Crow's Cameo
#6 Lucas and Felix's Race
#7: Peyton first met Chris Keller in the Tree Hill Record Shop
I didn't remember how Chris was introduced to the series until I saw him when Peyton was hanging up flyers for the all ages night!