Alyson Hannigan 1989, her first regular role on a TV series came when she was cast in the short-lived ABC sitcom "Free Spirit". As a teenager, Hannigan babysat for the children of her future "How I Met Your Mother" costar, Bob Saget. In 1997, Hannigan was cast to play Willow Rosenberg, Buffy Summers' best friend, on the television series "Buffy the Vampire Slayer". The show became a success, and Hannigan gained recognition, subsequently appearing in several films aimed at teenaged audiences, including "American Pie" (1999), "Boys and Girls" (2000), "American Pie 2" (2001), and "American Wedding" (2003). She also had a guest
Buffy the Vampire Slayer describe the fictional universe in which "Buffy" and related stories take place. The franchise has inspired "Buffy" action figures and merchandise such as official "Buffy/Angel" magazines and "Buffy" companion books. Eden Studios has published a "Buffy" role-playing game, while Score Entertainment has released a "Buffy" Collectible Card Game. The storyline was continued in a series of comic books produced by Joss Whedon and published by Dark Horse Comics, which serve as a canonical continuation of the television series. The series, which began in 2007 with "Buffy the Vampire Slayer Season Eight", followed by "Buffy the Vampire Slayer Season Nine" in