Director
Daughter
Mother
Doctor
NOTE: for the different parts, you can distribute the roles so every girl gets a chance to participate

Director: All right, everyone! Let's get ready! Lights, camera, action!
(everything said below is monotnonous and boring)
Daughter: (entering) Mom, I'm sick.
Mother: You're sick?
Daughter: I'm sick.
Mother: Should I call a doctor?
Daughter: Okay. (lays down)
(Mother pretends to dial a phone. On the other side of the stage, doctor answers.)
Doctor: Hello?
Mother: My daughter's sick.
Doctor: Okay. I'll be there in a minute.
(knock on the door)
Mother: Come in, Doctor.
Doctor: (checks her out) She's dead.
Mother: Oh.
Director: No, no, no! This is so boring! We need some more humor! Make it funny people! Lights, camera, action!

Continue using basically the same dialogue and replaying the same scene, adding humor (have the girls laugh hysterically after their lines), action (have the girls doing karate moves throughout the skit), valley-girl style (add "like, you know" and stuff like "I broke my nail and it made me sick" or "Don't let the doctor in till I blow dry my hair!", etc.), drama (over emphasize everything), musical (have them say the lines in a sing-song voice; opera style is hilarious!) and most important is the part below:
(if you're in a building, dim the lights!)
Director: All right, let's add supsense, the audience loves that. Lights, camera, action!
Daughter: Mom, I'm sick.
Mother: Stop! (daughter freezes in position. Mother asks mysteriously, preferabl holding a flashlight upwards against her chin to creat a mysterious effect) I wonder..is she really sick? Or is she just trying to get out of school? Go! (daughter unfreezes, Mother turns off flashlight and speaks normally) Do you want me to call the docor?
Daughter: Yes.
Mother: Doctor, my daughter is sick.
Doctor: Okay, I'll be right over there.
(When the knock is heard) Mother: Stop! (again, everyone onstage freezes) Who is that? is it realy the doctor? Or is it the ax-murderer from across the street? Go! (again, they unfreeze, Mother answers the door) Come in doctor.
Doctor: (examines her) I'm afraid she's--
Mother: Stop! What will she tell me? Is it an infection? Is it an incurable disease? Or is she dead? Go!
Doctor: I'm afraid she's--
Director: CUT! Lunch break! (everyone leaves)

For those of you who didn't get it, the final one HAS to be suspense. The suspense part is that the "movie" is cut before we find out what happens to the daughter. And please, DON'T read from the script word for word. Leave room for creativity, and this can be an AWESOME skit!