What happens when you combine bleach and ammonia?

Very bad idea! This is a potentially fatal mixture which will release toxic vapors.

Bleach contains chlorine when it reacts with ammonia a very toxic chloroamine is formed.

When you combine bleach and ammonia, the two react to form many toxic products, including chloramine, dichloramine, nitrogen trichloride and hydrazine. But, if the reaction goes through all the way, it forms non-toxic nitrogen. The equation is as followed:

NH3+NaOCl --> NH2Cl+NaOH

NH2Cl+NaOCl --> NHCl2+NaOH

NHCl2+NaOCl --> NCl3+NaOH

NH3+NH2Cl+NaOH --> N2H4+NaCl+H2O

N2H4+2NH2Cl --> 2NH4Cl+N2

I would not recommend it unless you have proper safety equipment, a fume hood and are doing it under supervision of a experienced chemist.