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

Anya: (in a girls voice) "Dear Lisa, as write this, I am very sad. Our president has been overthrown...(man's voice) and replaced by the benevolent General Krull! All hail Krull, and his glorious new regime! Sincerely, little girl."
Lisa: (groans)

Michelle Obama: That's right, Lisa, as an avid organic gardner I've read your blog.
Lisa: Flotus1 is First Lady of the United States, one.
Michelle Obama: Yes, I wanted just flotus, but someone had it.
Ralph: That's me because I swim with my flotuses on.

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!

Son, a woman is a lot like a... a refrigerator! They're about six feet tall, 300 pounds. They make ice, and um Oh, wait a minute! Actually, a woman is more like a beer. They smell good, they look good, you'd step over your own mother just to get one! But you can't stop at one, you wanna drink another woman!

Homer