We also have a new segment from the Argentine telenovela, Verano Eterno posted for your edification. Amid the rapid banter, we heard:
[Caption 66, Verano Eterno > Fiesta Grande > 13]
"Ni loco" or "Ni loca" (for a female speaker) is basically a short-hand way to say "Not even if I were crazy," "No way" or "Not on your life."
Here are a few more short but colorful "ni" expressions that mean essentially the same thing:
Ni en broma
"Not even as a joke / No way"
Ni en pedo
"Not even drunk / No way"
Finally, there are some other phrases we thought of where "ni" + "que" means something like "como si" in Spanish. "Ni que" might be translated into English as "it's as if" or (with a negative slant) "it's not like." Here are two examples:
¿Por qué me gritas? ¡Ni que fuera sordo!
"Why do you yell at me? It's as if (you think) I'm deaf!"
Ni que fuera adivino, para saber lo que piensas.
"It's not like I'm a fortune teller who knows what you're thinking about."