(Sub-)stellar variability: from 20 M$_{\odot}$ to 13 M$_{\rm Jup}$
  Massive early-type stars vary; low-mass late-type brown dwarfs vary, too. I will make a short, but illustrative, summary of my previous studies on stellar and sub-stellar photometric variability (including the discovery of the most variable brown dwarf in the whole sky), and explain how amateurs can help professional astronomers with our investigations. 
J. A. Caballero
astro-ph.SR