When Peyton's phone rings during her conversation with Mia, her ringtone is a song featured in the Family Guy episode "McStroke" (season 6 episode 8), which includes a scene making fun of One Tree Hill. The song goes: "High school is such a serious thing. These problems matter."
Quentin's jersey number is 44.
Mouth's "coverage" of the Ravens game is simply ludicrous. For one thing, the camera he's carrying is an EFP - electronic field production. Though small and lightweight, they are not as high-quality as the ENG (electronic news-gathering) cameras that most any television station would use. Mouth is also taking notes while the game is going on, which is silly because any sports reporter would know to never stop filming - you never know what could happen, and you wouldn't want to run the risk of not getting it on tape. For this reason, stations typically send out a team of a videographer and a reporter to cover something as involved as a sports game.
When we see Lucas' buddy list on his computer we see Haley's screen name is BigFtHunterHJS. This is in reference to Lucas' goal in his yearbook in episode 4x19 "Ashes of Dreams You Let Die": To write the next Great American Novel and to find Big Foot before Haley.
When Lucas is online, we can see that his buddy list includes Lindsey Strauss (Lindsey), Scott23 (Nathan), BDavis (Brooke), Marv (Mouth), JunkYrdDog (Junk), Fergielicious (Fergie), and BigFtHunterHJS (Haley).
We find out that Millicent's last name is Huxtable.
When Dan tells Nathan of his attempted suicide in prison, he states that he tied a rope around his neck. In the actual episode, he used a sheet from his bed in the prison cell.
Lily also just turned 5 because she's only a few days older than Jamie, although there is no mention of her birthday.
Goof: Jamie's birthday was the same day that the group graduated high school which was probably in June, now his birthday is during the school year because there is still basketball going on.
Goof: When Skills and Peyton are walking on the bridge, talking about how difficult it was to find a Wii, he's clearly carrying a bag with a Wii (supposedly to him). It was definitely a fake, because the real box of the Wii is heavy and he's carrying the bag with two fingers!
And in the later scenes, when he's packing the Wii as a birthday present, he angles it like it's so light. He does the same when he gives Jamie his birthday present.
This is the first time that Deb and Dan have seen each other since Dan went to prison.
Jamie's 5th Birthday Presents:
Brooke - Check for an amount with "a lot of zeros"
Lucas - Dr. Seuss' Hop on Pop book
Dan - Nathan's No. 23 Tigers Jersey
Skills - Wii Game Console
Mouth - Legos
Lindsey really loves the color blue.
Goof: Jamie's number five candle is blown out in close up shots and lit when shown from far away.
Millicent says that she can't go to Omaha because the closest Clothes over Bro's location to Omaha is the one in Tree Hill. But in Episode 5.04 Victoria mentions a store in Houston. Houston is closer to Omaha than Tree Hill.
When Nathan and Haley are talking on the couch while Deb plays with Jamie, Haley takes a cup of wine from Nathan with her right hand, but in the next scene she has it in her left hand.
This is the first episode that the audience hears Haley call her mother-in-law, Deb, "Mom." Haley had previously referred to her as "Deb" or "Mrs. Scott."
Goof: The monkey that Brooke has when Chase enters the room goes into the cot at one point and the next second is back in her hand.
Goof: When Nathan and Haley are in bed at the start, the covers that Haley is in keeps changing from a duvet to a throw a few times.
The voiceover at the end of the episode is used again at the end of the series finale, "One Tree Hill".