Radio-loud Active Galactic Nuclei, especially blazars, are sources known to be extremely variable over the whole electromagnetic spectrum, from radio to gamma-ray energies. Until now, the Large Area Telescope (LAT), the primary instrument on board the Fermi satellite, has detected more than 850 sources that are likely to be associated with AGN. Among them, during the first 3.5 years of Fermi observations (i.e 2008 August 4 - 2012 February 4), 91 sources underwent at least one flaring episode at gamma rays. We will present and discuss a list of AGNs with daily fluxes brighter than F(E $>$ 100,MeV) = 10$^{-6} ph, cm^{-2} s^{-1}$, the threshold set by the LAT Collaboration for issuing an Astronomer's Telegram, and investigate the general characteristics of the selected sample.