Because I'm a crazy person...
Music Fighter! Summary and partial translation. Just the more interesting and funny parts, so you need to watch it to follow along as I didn't translate everything they said.
Ai: I brought my own thought out plan: You guys! Do you really know Momusu?!!
Quiz Battle
First, a writing quiz
Risa: Eh? Wait! What? (her usual reactions

)
Question: What is MM's first single and sale date?
Risa: There's two dates.
Reina: This is an awesome pen!

Answer: Morning Coffee 1/28/98
Kajiwara: Why did you write 6/21??
Reina: That's because I don't know (when it went on sale)
Question: Write the full names in kanji of 1st gen.
Nishino smacks Koharu
Koharu: What? What? What?!
Linlin: Kusumi, are you a Japanese person?!
Ai: Isn't it the other side? The back.
Kajiwara: This is bad. This is way too rude.
Michishige: We can't show this.
Iida's name, Kaori, Mittsi wrote the wrong kanji for "Ka"
(During Koharu's showing of her board)
Somebody (I think Ai): Are you an idiot?
Narrator: Kusumi, you were way off.
Question: Who put the "." in for Morning Musume.
Eri: This is normal (not in a weird way) answer, right? If you think simply, you know, right?
Koharu: I know this!
Ai: A famous person.
Aoki: Believe in yourself.
Ai: This person's on TV.
Eri: Sorry! (Upfront's CEO)

Kajiwara: Super famous and is on TV a lot: Aso Taro (Prime Minister of Japan)
Answer: Ninety-nine Yabe-san
Question: What is the song MM sang for their debut on Kohaku
Nishino: Linlin, are you confident in your answer?
Linlin: Yes!
Junjun was missing the long vowel symbol for "machine" and then she puts it in the wrong place.

Answer: Daite Hold on Me!
Junjun: That was really close!
Ai: Not even close, not even close.
Question: Including all previous members which prefecture did the most members come from?
Nishino: Linlin, you know the answer?
Linlin: From that place.
Kajiwara: Linlin asked me to explain the question to her and I did and asked did you get it? She replied Haaa?!
Nishino: So you know the answer, right?
Linlin: That's right.
Nishino: Leader, go over there and see.
Ai: Haaaa?!
Kajiwara: You've gotten better! (He's making a reference to a previous MF where Ai-chan knows a certain joke method she learned from Tsunku, but when Kajiwara tried to do an example, she failed.

)
Answer: Hokkaido
Buzzer question
Question: The 2nd leader of MM...
Ai: Please listen to the full question.
Question: The 2nd leader of MM is Iida Kaori, but what is her nickname?
Answer: Kaorin
Question: Among all members, past included, who are 165cm or taller?
Junjun: Me?
Answer: Ishiguro Aya, Iida Kaori, Junjun
Koharu asks about herself.
Ai: When asked about her height, she replied she was 164.5cm
Koharu: No, no, I'm 164.8, so it's fine.
(Yossi is 163cm)
Question: Yuko's nickname is Yuu-chan, but please think of a new nickname.
Linlin: A blonde pig
Junjun: Nakazawa-chan
Linlin: This is unfair!
Kajiwara: A blonde pig is better, huh.
Question: "Antanya mottainai" What is the following line?
Aoki: No way, I pushed first.
Sayu: Atashi hontou nice body body body
Aoki: You know I'll get it wrong, so the least you can do is let me go first!
Question: We let an foreigner listen to a song. What song is it?
Answer: Happy Summer Wedding
Mittsi: Why is this song?
Question: We let an foreigner listen to a song. What song is it?
Kajiwara: (Too lazy to look up what song title he said, but totally wrong

)
Answer: Renai Revolution 21
Ai: Freebie question
Question: MM is known for an energetic greeting, but let's try it here.
Junjun: Just push the button for now!
Aoki: MM Aoki Sayaka. When I join MM, Morning Coffee....
Sayu: I feel we really didn't need to settle this.
Question: Sayu, who just joined, hit a sempai with a mic. Who was it?
Answer: Ishikawa
Sayu: It wasn't on purpose.
Singing shabondama had some head movement and hand movement. She didn't notice the mic flew, so when she heard from Nacchi who asked if she apologized to Rika yet, but Sayu didn't know what to do, so she never apologized.

Question: Please listen to the song. What is the following line?
Answer: Sexy beam
Question: Ai sings at karaoke the theme song, "Mito Komon," what is the real name of Mito Komon.
Sayu: Is Mito Komon a person?
Answer: Tokugawa Mitsukuni
Aoki's answer was close enough, so they counted it.
Nishino: The last question is 100 points.
Question: Who is the person that mistakens when she goes on stage, returns backstage, and later sings in costume?
Risa: You!
(Do the Risa dance!

)
Nishino: So, leader, how was it?
Ai: This is.. I don't know anymore. (Ganten? T_T I can't get what she says)
End
Sayu talks about how on the last show she was complaining that she didn't get any singing lines, but this time she got singing lines, so she thanks MF for the chance.