Sci Fi Channel President Bonnie Hammer threw the cable network’s staff an impromptu party last week complete with Vampire Bloody Marys, Big Foot-long Hot Dogs, Chicken in a Casket and Chocolate Chip Doherty Ice Cream. Ms. Hammer assembled the refreshments in honor of the blockbuster performance of the new “Sci Fi Thursday” lineup. Viewership built throughout the 9 p.m.-to-11 p.m. block, and each show boosted its time period average among 18- to 34-year-old viewers by triple-digit percentages year to year. The series premiere of “Mad Mad House” kicked off the night, drawing about 1.57 million total viewers, according to Nielsen Media Research. It was followed by the second season premiere of Shannen Doherty-led “Scare Tactics,” which tallied about 1.58 million viewers, as well as the debut of the sexy animated series “Tripping the Rift,” which scored almost 2.1 million viewers.