When they announce the contest for the dance off, the spoon that Janey is holding repeatedly switches hands between shots.
When Lynne is in the mall getting ready to go to the printing shop her shoes are brown with pink socks, and when they start passing out invitations her shoes are black with white colored socks
When Jeff and his dad are at the dining room table, and his dad is asking him, "Can you win this thing?" the top of the sugar container is alternately on/off between shots.
When Janey is going to her seat on the bus, she is carrying a huge pile of books. When they are running to the place where Lynne is babysitting, she no longer has her books.
Jeff's shirt changes from red to blue/purple after the first practice session with Janie.
In the beginning of the movie when Janey is in front of the class and talking about herself, she tells that she was with her Army father on Guam. Guam has Navy, Marines, and Air Force, but no Army.
During the first audition, when Lynn gets stepped on and thrown on the floor by her dance partner, behind them you can see Jeff's and Janey's dance doubles.
About an hour into the film there's a montage of Jeff and Janey practicing in the park. In one sequence Maggie is sitting in a tree looking on as Jeff jumps off of it. Jeff lands and turns to look at her. The shot of her reaction was flipped, as the text on the Pepsi can she's holding is backwards, and the tree she's sitting on is now on her left (screen right) instead of her right (screen left). This was obviously done to match the direction of the shot of Jeff looking at her.
Obvious stand-ins for Janey and Jeff during the dance auditions.
When Richard Blade announces Natalie and her partner, and Janey and Jeff, as co-winners of the competition, he pronounces Jeff's last name as "Malane" instead of Malene. He pronounces it correctly at the beginning of the show.
Natalie's words don't match what she is saying when she tells the punk at her party to give her her cardboard cut-out.
At Janie and Jeff's first practice, the music starts playing without Jeff actually turning on his radio.
When Zach knocks on the door of the bathroom when Janey is taking a bath, you can clearly see the top of a crew members head.
When Janey and Jeff first meet in the rehearsal hall, their mic packs are very visible under their clothing.