After Les throws the toothpicks at Toby one toothpick sticks to Toby's shirt. It appears and disappears during their ensuing argument.
During the conversation with Les's parents about the $700 photo, the gun on the eagle lamp disappears during closeup shots of Toby.
Toby and Les are in the apartment, quarreling. The latter, wearing white boxers, is attacking Toby physically. Then comes a cut and now Les is wearing black jeans. Then we have another cut and now he's back in his boxers.
After Toby stabs Blaine while filming "A Slice of Life", the director calls for a "reset" of the scene, so they may do a retake. Blaine completely removes his blue running jacket, and when the camera cuts to another angle, Blaine is seen to be removing his jacket again.
After 31 minutes into the movie when Toby and Les are celebrating going over the swag loot from the party a box of Trojans appear for a moment on the table to the right of Toby where there were none before and then a moment later they are no longer there. All the while they were going over the t-shirts from the bags.
Microphone being used by the MTV interviewer backstage at the awards was not a wireless mic. Just a cheap "wired" mic without a cable.
When Les makes a camera gun he loads it with a bullet that already has a primer that has been struck by a firing pin.
During one of Toby's interview for Slice Of Life the clapper they use is visible just long enough to see that it is for Delirious and the director is Tom DiCillo. The director of Slice of Life is named Corey.
When Les and Toby enter the hotel to attend K'Harma's birthday party, Toby pushes the down button to call the elevator. This is obviously in error as they entered on the ground floor, and the room would be on a floor above them.