Is there a facebook ascii art TEXT generator?

For now, no. You cannot text via Facebook. Though they recently made it possible to have FB on your phone. So I'm sure texting is coming soon as well.

There isn't one code for everyone. Each individual person/account has his/her own specific activation code.

Press "edit" then it should say something like "customize"

I don't know but what i would do is do what ever art you do and take a good picture of it and put it up in your pictures on facebook.