The skateboarder who was in the cake mix with the other kids also has a trophy at the end of the race, but he couldn't be pronounced a winner because he had no tube and he didn't start the race like the others.
Numbuh4 was trapped on the small island but in P.O.O.L., he already learned to swim.
Numbuh 4 grows a beard while stranded on an island in the tubing race despite being far too young to grow one.
RESPONSE: It was a joke
At the end, the announcer says everybody won except Numbuh 2, but Numbuh 4 and the Delightful Children lost as well.
Numbuh 5: Looks like our race is taking a bit of a detour!
Numbuh 1: Yeah! And I've got a feeling it's no accident!
Tommy: I've got a feeling I'm gonna hurl!
Numbuh 5: Do it on the chair, and you're swimming home, kid!
Delightful Children: On your marks, get set... Bye, bye!
Father: Ahh, I love baking. Why, it's more than a hobby to me.
Numbuh 4: Numbuh 3? Over here. Help! You gotta save me!
Numbuh 3: I can't shave you right now, Mr. Old Man. I'm racing!
Numbuh 4: Kuki, it's me! Numbuh 4!
The Kid: Nice tube.
Numbuh 3: I decorated it myself.
The Kid: Really? Maybe you and I could get together after the race and share some decorating tips.
Numbuh 4: Hey!
Numbuh 3: That sounds great.
Numbuh 4: Hey, you get away from her, you Fly-Boy!
Commentator: Wallabee Beatles, stranded on an island called "Heartache". A loser in tubing and a loser in love.
Numbuh 4: Love?! What are you talking about?
Near the end of the episode, when (almost) all of the participants in the Tubathon receive trophies, Jessica from Operation: RABBIT makes a cameo appearance.
Sixth full-length episode.
Operation: C.A.K.E.D.-F.O.U.R. is a Numbuh 2 episode.
In Operation: C.O.W.G.I.R.L., Lasso Lass mentioned something that the KND might live in Mississippi, and this episode supports that fact since they could of been having the Tubathon in the Mississippi river.
Villains: Delightful Children From Down The Lane & Father.
Fanny (a.k.a. "Numbuh 86) is metioned to be in the Tubathon for a split second in this episode, but is not shown racing.
The name of the business that built the 'skate park' is called Evil Adult Industries.
This episode was first run as the last episode of a Codename: Kids Next Door Presidents' Day marathon on Cartoon Network.
Numbuh 65.3 has a cameo appearance in this episode.
First time that anybody has referenced Numbuh 4's and 3's love relationship directly.
First "C.A.K.E.D." episode in which a cake doesn't actually appear.
"The Kid" has a slightly different voice than the one he had in his last appearance.
The commentator mentions Fanny Fulbrite (Numbuh 86) during the home stretch, but she is not actually seen.
Muffy Jenkins, the girl who pops Numbuh 4's tube,makes an appearance. She is mentioned in "Operation: P.R.E.S.I.D.E.N.T." and "Operation: P.I.N.K.-E.Y.E.".
Numbuh 4's tube is named Tubezilla.
"The Kid" makes a second appearance in this episode.
Credits: Numbuh 1 and 5 talking about Numbuh 2 and then they say he wasn't in last place. Meanwhile, Numbuh 4 is still stuck on the island.
This is the first "C.A.K.E.D." episode in which Father appears.
Numbuh 2 episode.
"C.A.K.E.D.- F.O.U.R." stands for Children's Annual Kompetition Exposes Devilishly Fiendish Operation Up River.
From this episode, we can assume that Numbuh 2's father is deceased.
Numbuh 4 is upset that "The Kid" likes Numbuh 3.
This brings up the conclusion that each season has its own "Operation: C.A.K.E.D." episode.
Apparently, Father can be harmed by his own fire.
Numbuh 2's tube is named Betsy.
Numbuh 5's father, Numbuh 1's mother, & Numbuh 4's parents aren't in the audience of the Tubathon.
Coconut on Island:
Once we first see Numbuh 4 on the island with a beard, you can see a coconut with a face on it. This is an obvious reference to the movie, Cast Away.
Numbuh 2's (and his father's) use of the word 'Farfigtubin' is a reference to an old Volkswagen commercial where driving the car gave you a joy of driving, which they called 'Farfignuten'.
Father: (To Numbuh 2) Your father was a liar!
The entire conversation between Numbuh 2 and Father discussing Hoagie's father is extremely similar to that of The Recruit between Colin Farrell and Al Pacino about his father who was said to be in the CIA. Farrell denies any attempt to try and convince himself that his father wasn't in the CIA and trusts his father and often gets extremely angry when Pacino tells him otherwise. At the end of the film, there is a hint that his father was in the CIA and was telling the truth, exactly like when Ms. Gilligan stated a hint revealing that Hoagie's father won the races etc.
The race's commentator is a clear parody of legendary football commentator Howard Cosell.