I play up to eight games at the same time. Currently it's mainly the Witcher III though as I finally got around to buying it with 50% off and it's completely addicting.
Mixed with some Fallout 4, Carmageddon, Wreckfest and some WoW/Path of Exile and GTA: San Andreas. If I feel like it FIFA and CS:GO, but haven't had any interest in playing those two games the last month.
I'm addicted to Nuclear Throne. Seriously. I uninstalled it twice, just to install it back the next day. I want to stop and try new games but it seems that the thrill of total shooting chaos is a drug. You have been warned.