MONDAY: BEVERLY HILLS, 90210
TUESDAY: DAWSON’S CREEK
YESTERDAY: THE O.C.
TODAY: ONE TREE HILL
BROOKE-LUCAS-PEYTON
How It Started: Lucas had a crush on his half-brother’s girlfriend, Peyton, but ended up dating her best friend Brooke in season one. It wasn’t long, though, before Lucas and Peyton couldn’t hide their mutual attraction and began sneaking around Brooke’s back. When Brooke found out the real reason Lucas broke up with her, she ended her friendships with both of them, and the Leyton versus Brucas war began.
How It Ended: Peyton and Lucas realized they couldn’t move forward with their relationship after hurting Brooke so much. By the end of season two, Lucas realized how much he missed Brooke and in the beginning of season 3 they got back together. At the end of the season, however, Peyton also realized that she was in love with Lucas and told Brooke–effectively ending their friendship. Brooke broke up with Lucas, in part because of this, in the beginning of season 4. It took some time but Lucas finally realized he was in love Peyton, too, and Brooke gave them her blessing.
Key Episodes: 1.8-1.15, 2.23, 3.9, 3.21-3.22, 4.1-4.3, 4.8-4.12, 4.15
YouTube Evidence: One Tree Hill–Classic Love Triangle; One Tree Hill–Love Triangle; Brooke/Lucas/Peyton Love Triangle; Brooke/Lucas/Peyton: Tikal
LINDSEY-LUCAS-PEYTON
How It Started: When Peyton returns to Tree Hill at the beginning of season 5, she’s surprised to find out that Lucas is in a serious relationship with Lindsey. Lucas, still angry that Peyton turned down his marriage proposal a few years back, continues his relationship with Lindsey and denies that he has any feelings for Peyton. One night, after Lucas and Peyton share a kiss and Peyton thinks they will be together, she finds out Lucas and Lindsey are getting married.
How It Ended: On their wedding day, Lindsey leaves Lucas at the altar after realizing that he is still in love with Peyton. Lucas spends the next few months trying to get Lindsey back and blaming Peyton for their break-up. Season 5 ends with a love triangle cliff-hanger: Lucas is at the airport and calls someone, asking “Do you want to get married tonight?” It isn’t until the season 6 premiere that we find out he called Peyton. She accepts his new proposal and they get engaged.
Key Episodes: 5.1–5.9, 5.11-5.18, 6.1, 6.05
YouTube Evidence: One Tree Hill–Lindsey/Lucas/Peyton, One Tree Hill–Peyton/Lucas/Lindsay; Lindsey/Lucas/Peyton–The Hardest Thing; The Comet Movie Trailer
OTHER TRIANGLES TO CONSIDER
Nathan-Peyton-Lucas
Nathan-Haley-Chris Keller (not included above based on poll results)
Dan-Karen-Keith
Mouth-Rachel-Cooper
Jake-Peyton-Lucas
Haley-Nathan-Carrie
Millicent-Mouth-Gigi
TeenDramaWhore 
I posted this youtube video earlier that I found a while back … it’s like THE best Brooke/Lucas/Peyton triangle vid ….
And I also added one that I made incase anyone was interested in seeing it…
I considered including that first one in my YouTube evidence but decided not to for some reason. Went back and added it now. There’s just too many good vids out there!
And your video is an excellent recap of season 3 Brucas v. Leyton. Nice job!