The Simpsons Episode 7.25 Summer of 4 Ft. 2

When her family goes away to a beach house for the weekend, Lisa decides to transform herself into a new, cooler person. Her first step is abandoning her old, dorky clothes in favor of tricked-out threads. She also hides her egg-headed impulses by dumbing-down her vocabulary and pretending she doesn't read books anymore. Soon, Lisa befriends Erin, a cool but disaffected local kid, and her friends. Lisa's transformation is complete: she is popular. Of course, Bart is seething with jealousy and comes up with a plan to ruin his sister's popularity. Bart shows Erin and her friends Lisa's elementary school yearbook to prove what a good student and a goody-goody his sister really is. Bart's plan backfires, however, when Lisa's new friends turn out to like her anyway, even if she is a nerd.