Edna Krabappel is Bart's fourth grade teacher on the show The Simpsons.  Edna is voiced by Marcia Wallace and is portrayed as a lonely divorcee.  She previously dated Skinner, but now mostly will throw herself at anything that's remotely willing.

Edna Krabappel Quotes

Now, I don't want you to worry class. These tests will have no affect on your grades. They merely determine your future social status and financial success. If any.

Mrs. Krabappel

Bart: Mrs K, you have to get out of here. When was the last time you washed your hair?
Edna Krabapple: Hmm, two weeks ago...
Bart: Well, that's better than me, but still, you gotta get out

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!

(Bart shows the whole classroom the tape for his project called, "How Kittens Are Born: The Ugly Truth")
Bart: and here comes Snowball II. This is the one we kept.
All: EWW!!
Bart: We were gonna keep the gray one, but the mother ate her.
All: EWWWWW!!
Martin: Mrs. Krabappel, he's traumatizing the children!
Mrs. Krabappel: As usual, I agree with you, Martin. Bart, shut that off and take your seat immediately!
Bart: Oh, look! This is really cool. When I hit reverse, I can make 'em go back in.
(The whole classroom screams)