Recorded at The Pack Theater in Hollywood in front of a live audience, it's our 200th Episode Spectacular! We took a look back over the first 199 episodes with some of our favorite past guests, culminating in the ultimate Quiz Showdown! In this episode we talk to Jacob Harper (@JacobRayHarper), from episodes 7 and 8, about mannequins spying on us. Joey Clift (You Should Love Wrestling Podcast, @yslw), from episodes 58 and 59, about birds with stressed out gonads. Keith Saltojanes (@KeithSaltojanes), from episodes 111 and 112, about using stem cells to live forever. JPL Scientist Josh Willis (@ClimateElvis), from episodes 118 and 119, about the Philae lander and Rosetta comet orbiter. Nuclear Physicist Kevin Peter Hickerson (@KPHickerson), from episodes 135, 136, 168 and 170, about mysterious gas plumes on Mars. And Markeia McCarty (@MarkeiaMccarty) from episode 175 about centaurs, asteroids and holiday science. Plus Jesse's Fact Corner with Jesse Klein (@JessKlein1) and Quiz Maestro Sara Clarke (@sara_clarke) dishes out a quiz for the ultimate prize of Science Jerks Champion!