The World Community Grid is a great initiative that can use your computer while it's idle (or not used extensively) to run simulations. What kinds of simulations? Currently, it's about finding the candidates for antiviral drugs for HIV, TB, Zika or Ebola, right next to the research that can help scientists understand neuroblastomas. You can even set it on a smartphone and allow computations to be done only while it's recharging, although the stronger computer the better for obvious reasons. Anyway, it's a lot like SETI@HOME, only WCG has actually produced results.
I can try and help you set it up if there would be any problems and the related BOINC wiki would not seem clear.