The best Jason Mantzoukas movies and TV shows include mostly geek-friendly genre offerings, with several comic book, sci-fi, and fantasy properties under his belt. In what should come as no surprise to anyone who follows Mantzoukas and his acting career, he started off as a stand-up improv comedian. He first wrote sketches in his junior and senior years of high school and then joined the Upright Citizens Brigade in 1998, where he learned under Amy Poehler.