Lisa Marie Simpson, voiced by Yeardley Smith, is Homer and Marge's oldest duaghter and the middle child on The Simpsons.  Lisa is very intelligent, plays the saxophone, is a vegetarian, Buddhist, and definitely a bit of a young political activist.  She's basically the complete opposite of her brother, Bart.

Lisa Simpson Quotes

So now Andy is a TV writer? Loser.

Lisa

Mom, it's trash talk. You know how guys say mean things to their friends the way women say nice things to their enemies?

Lisa

The Simpsons Quotes

Homer: (Wearing glasses) The sum of the square roots of any two sides of an isosceles triangle is equal to the square root of the remaining side!
Man: (From inside a bathroom stall.) That's a right triangle, you idiot!
Homer: D'oh!

Homer: Aw, twenty dollars? I wanted a peanut!
Homer's Brain: Twenty dollars can buy many peanuts.
Homer: Explain how!
Homer's Brain: Money can be exchanged for goods and services.