  We consider different scenarios of collisions of compact objects (clouds,
massive stars, supernova shock waves, or young pulsars) with jets in active
galactic nuclei. The purpose is to find out if such collisions can become
plausible explanations for the gamma-ray production in blazars. We conclude
that the relativistic proton beam - cloud collision scenario has problems with
explanation of the $\gamma$-ray spectrum in the observed energy range from
blazars. As a result of collisions of massive stars, supernova shock waves, or
young pulsars with the jet plasma, a highly oblique shocks should be formed.
These shocks can accelerate electrons, protons to energies high enough for
production of $\gamma$-ray photons observed in blazars. However, in order to
produce observable $\gamma$-ray fluxies, the particles should be accelerated
strongly anisotropicly, which may be the case of highly oblique relativistic
shocks in jets of AGNs.
