Presented by Movieside and the Music Box, this fourth annual marathon of horror and sci-fi movies begins Sat 4/10 at 11:30 AM and runs for 14½ hours, wrapping up at 2 AM Sun 4/11. Tickets are $24, or $20 in advance at Music Box, 3733 N. Southport; After Hours Movie Rentals, 915 Foster, Evanston; Laurie’s Planet of Sound, 4639 N. Lincoln; and Doors open at 11 AM for early access to the vending tables in the lobby, and patrons can leave and reenter the theater.

This year’s special guest is writer-producer-director Larry Cohen, who made a name for himself in the 70s with the low-budget classic It’s Alive (1974) and went on to direct not only two sequels (It Lives Again in 1978 and It’s Alive III in 1987) but God Told Me To (1976), The Private Files of J. Edgar Hoover (1977), and Q (1982). Cohen is still going strong at age 71; as recently as 2002 he wrote the nifty Colin Farrell thriller Phone Booth.

This year’s lineup begins with a half-hour of vintage trailers, followed by Gordon Douglas’s Them! (1954), about giant ants terrorizing the American southwest (noon); Mario Bava’s super-low-budget Planet of the Vampires (1965), said to be a major inspiration for Alien (2 PM); John Carpenter’s debut feature, Dark Star (1974), a satire about astronauts who fly around the universe blowing up planets (3:30 PM); Mikes Hodges’s Flash Gordon (1980), which revived the old comic strip with a score by Queen and Max von Sydow as Ming the Merciless (5:15 PM); Cohen introducing his Q, about a winged serpent flying around modern-day New York City (7:30 PM); Tobe Hooper’s Lifeforce, another tale of vampires in outer space (10 PM); and Carpenter’s They Live (1988), a satire of mass media in which aliens control humans through TV. —J.R. Jones