This is a hackathon with a Halloween twist. Taking place at Ravensbourne as part of London Transmedia Fest and London Games Festival, the idea is to build a project that will scare the living daylights out of people (surprise tactics are encouraged).
The most frightening project (can be an app, website, arduino-based or other) will be featured on MSN UK's website, which has 17 million unique views per month. Not bad.
It's being organised by Digital Shoreditch (www.digitalshoreditch.com), tickets are £6.66 (this covers pizza and refreshments), and sign up is here (limited tickets): http://scarathon.eventbrite.co.uk