When Deebo is riding his bike to Craig's house the first time, one shot shows Deebo nearly on the driveway. Just then Smokey and Craig remove all their valuables. If this were true, Deebo should have seen these. But then in another shot, Deebo's bike is shown just coming onto the driveway. In that amount of time, Deebo should have been further up the driveway.
Not really a mistake but most people miss this. When Craig is talking to his girlfriend on the phone and she asks who he "went to the show with" if you look real close you will see a guy lying in her bed in a pair of Dicky's pants.