I shall be answering this with Clavichord! ([link]

1. Do you go by any nicknames?
Only my friends can call me this, but I am also known as Clavi. (I will take time out of my day to kill you if you call me Clavi!)

2. What gender are you?
I'm a mare.

3. What species of pony are you?
I'm an earth pony.

4. What's your cutie mark, and how does it describe yourself?
Well my cutie mark is a few piano keys, it describes my ability to not only play the piano, but also play your emotions.

5. What's your occupation?
Nothing glamorous. I'm a music teacher in Ponyville.

6. What are some common occupational hazards you come across?
Fillies and colts! Whether it's placing a thumbtack on your chair or hurting your ears when they try to play an instrument, my students are always a hazard to me.

7. Do you like Ponyville?
It's a fairly nice town, though that pink pony disturbs the peace sometimes. Along with her friends who I'm beginning to think are crazy.

8. Have you ever been to the Grand Galloping Gala? If not, have you ever dreamed of going?
I played the piano there once actually, but I was very upset that evening (I have my reasons) and lost control of myself. My music caused a full blown brawl!

9. Do you have any hobbies aside from your job?
Other than playing piano and calming Katt down (not an easy thing to do), no. Well I guess I go running with Allegro, but that pony has so much more energy than me.

10. What are your quirks? As in, what makes you unique?
*cough* Well, I guess you could say I'm hot headed. I guess the only unique thing about that would be the fact that it's really not hard to calm me down if you sincerely didn't want to upset me. Otherwise, be prepared for me to play you a very stormy melody. I would also like to say I think of myself as loyal. I will never, ever leave my friends and family and I think that's hard for some ponies.

11. Can you stand on your forehooves?
No.

12. Can you stand on your head?
No. What kind of question is that?

13. Favorite type of music?
Anything, because I can play pretty much any genre.

14. What's your favorite food?
Coffee cake!

15. Do you have a crush?
Not right now, but I think somepony has a crush on me.

16. Do you have any pets? Name them.
Ricky, my little white mouse.

17. Nightmare Moon has escaped from the moon and has come to bring eternal night all over Equestria. What do you do?
Well really, what can I do?

18. Who is your idol?
Uhm, none?

19. Guess what. The game.
W-what? I don't even know what that is, but Jojo says you made her lose. Am I missing something?

20. Favorite flavor?
Cherry!

21. What would you find at the end of the rainbow, if a pot of gold doesn't suit your tastes?
Can't I just have the gold?

22. Are you gay?
Never been attracted to a mare, but you never know.

23. What's your favorite season?
Spring, I love rain.

24. Who are your friends?
Katt, Allegro, Poppy Sprout, Slumber Mist. and Riley Riddles. I've gotten to know a pony by the name of Octavia recently though.

25. Now who's your BEST friend?
Misty (Slumber Mist) is my best friend. We've known each other since we were fillies, and she's such a calm pony.

26. What made your cutie mark appear?
I was playing piano (very strange for an earth pony, but not impossible, when a gang of mean fillies came in. They always made fun of me because I was a little nerdy and I hadn't gotten my cutie mark like them. I ignored them and continued playing, but then they started taunting me. After a while I felt really bad about myself, and I guess my playing projected the feeling onto them. Not only did they suddenly feel sad, but they understood why. They stopped taunting me and even apologized, and then they started cheering and pointing at my flank. I looked and there it was.

27. You find a dead pony in your room, and the police have your house surrounded. What do you do?
What do you do when you look very suspicious!? I mean did I just find the body or did I kill them?!

28. LOOK, IT'S PRINCESS CELESTIA.
I doubt she'd be in my house.

29. Gotchya~
No you didn't?

30. When's your birthday?
May 20th

31. Were you born in Ponyville?
Born and raised.

32. What kind of family do you have?
My mother is... my mother. I love her, but she has always been very protective. As for daddy, he's just been there for me. My sister would disagree, but she's always been difficult.

33. Are you scared of anything?
Losing my friends.

34. You see a parasprite on the edge of the road while you're walking into town. What do you do?
Squish it? Lure it with an apple?

35. There's an ursa major behind you.
In my house? I don't think it would fit in my house!

36. Gotchya again~
No you didn't, again.

37. Your favorite color of all time is...
Gray.

38. You ask a pony for directions. However, all she does is gasp loudly and gallop off at full speed. What do you do?
I would probably yell at her for being rude! And then I would find someone else who isn't a jerk!

39. A random stallion (if you're a girl)/mare (if you're a guy) strides up to you, tells you you're cute, and asks about your day plans. What do you do?
Ugh, I don't like being hit on! I'd most likely punch the idiot.

40. You take another look at them and decide that they're kinda cute. NOW what do you do?
I'd still be mad, but I guess I'd apologize for my punching him.

41. Roller coasters are...
Vomit inducing.

42. You're standing in a patch of poison joke. What do you do?
Rip the stupid plants out of the ground! I've already touched them.

43. You wake up the next day and find that the poison joke has taken effect. What's your symptom?
My fore-hooves have gone numb and now I can't play piano properly.

44. Can you speak two or more languages?
A little bit of french, mais pas bien.

45. You bought a new outfit from Rarity's boutique recently. She told you it really suits you, but it's very delicate and not machine washable. While wearing the outfit, a bully knocks you over into the mud. What do you do?
I get up and punch them in the face then go back to Rarity to ask what I do to clean it.

EARTH PONY PORTION
SKIP THIS PORTION OF THE QUIZ IF YOU ARE NOT AN EARTH PONY

1. So, you're a regular pony. How's life, hon?
Pretty good.

2. Are you jealous of the unicorns for being able to do magic?
Only the basic spells that allow me to lift stuff. Otherwise no because I enjoy being a piano playing earth pony.

3. Are you jealous of pegasuses for being able to fly?
It's pegasi, and no.

4. Erm... That was probably unecessary...
Yes, very.

5. So, what's your opinion on being a regular pony?
We rock.

UNICORN PORTION
SKIP THIS PORTION OF THE QUIZ IF YOU ARE NOT A UNICORN

Imma answer this with Riley Riddles

1. So, you can do magic, right?
Yeah, totally!

2. What spells do you know?
Memory, clarity, and thinking spells mostly.

3. Are you jealous of the pegasuses for being able to fly?
Oh yes! The view must be amazing!

4. If there was a spell you wish you could pull off, what is it?
Oh, I wish I could do a transportation spell! I'm so busy as a detective, and I have to travel a lot all day.

5. What is your biggest success involving magic?
I guess solving a recent case, where the pony who committed the crime kept leaving clues behind. Makes no sense to commit a crime and then leave hints so people can catch you, but whatever they want. Anyways, I had that thing solved in a day.

PEGASUS PORTION
SKIP THIS PORTION OF THE QUIZ IF YOU ARE NOT A PEGASUS

Using Katt!

1. Yay, you can fly, yay.
Oh my goodness, yay! I love, love, LOVE flying!

2. Do you air (no pun intended) from Cloudsdale, or were you born on the ground?
Yes! But I live in ponyville now with my marefriend, Slumber Mist.

3. Can you do any special tricks in the air?
I can do a lot of tricks! I can do flips, and loops, and all sorts of neat things! But I can't do nearly as much as that Rainbow Dash pony! I can't believe she's not in the Wonderbolts! I mean, c'mon, SONIC RAINBOOM!

4. Are you jealous of the unicorns for being able to do magic?
Oh, totally! But I'm not mad! I could do some awesome stuff if I could do magic!

5. Have you seen a sonic rainboom?
YES! And they are totally awesome!!!

And that concludes some of my OCs being...themselves.