Continuity mistake: At the end of "Dares", Ned's hair is dry after he gets out the kiddie pool, but in the last shot, his hair is wet.
Ned's Declassified School Survival Guide (2004)
1 continuity mistake in Dares and Bad Habits - chronological order
Starring: Daniel Curtis Lee, Devon Werkheiser, Kyle Swann, Lindsey Shaw
Art Class & Lost and Found - S3-E5
Other mistake: Ned paints a rather obscene painting and brings it up to his teacher. He had just painted the painting and his teacher gets angry at the school cutting the art budget, so Ned holds the painting against his chest. When he takes it off his chest, there is no paint on his chest and the painting had no chance to dry before he put it on his chest.