Now that the city’s most famous marathon has taken place, the Music Box and the Portage Theater will respond with marathons of their own. Music Box of Horrors, which begins this Saturday at noon, and the Portage’s Massacre, which kicks off next Saturday, October 20, are 24-hour celebrations of horror, suspense, and otherwise spooky movies, each with its own dedicated programmers and fans. It’s hard to say which one is the better event—the folks behind both marathons have really topped themselves this year. Each one contains an impressive mix of classics (The Golem and The Invisible Man at the Music Box versus The Black Cat and Hitchcock’s Frenzy at the Portage), cult favorites (Evil Dead 2 and Lucio Fulci’s The Beyond versus Return of the Living Dead and John Carpenter’s Prince of Darkness), and rarities (a beguiling-sounding 60s scare comedy called Dr. Terror’s House of Horrors versus an early David Cronenberg short called From the Drain). And both marathons will be projected almost exclusively from film—which is inherently scarier than video, as the upcoming horror flick Sinister informs us.