Sisters Alvin & the Chipmunks : Season 3 Episode 7

Brittany tries to join the Sisters, a club of the best-dressed, most popular girls in school. But in order to do so she has to avoid her own sister Jeanette, whose clumsiness and unpopularity would destroy her chances of getting into the club. Since she and Jeanette are working on a science project that involves taking care of a baby pig, this leaves Jeanette to do the project alone.