Full Fact (https://fullfact.org/), the UK's independent factchecking charity, spoke at one of our recent Meetups about their need for help building Lucene-powered automated factchecking systems. Many of us were inspired by their talk and several people offered to help on the spot. We thought the best way to bring together people to help might be to run a hackday during which we can use Lucene & Solr to build great software for Full Fact to use.
For some background you might want to read their excellent report on The State of Automated Factchecking (https://fullfact.org/blog/2016/aug/automated-factchecking/) and our blog (http://www.flax.co.uk/blog/2017/01/04/just-facts-solr-luwak/) on the event.
Facebook will be hosting at their 338 Euston Road offices - please let us know your full name and email when you sign up.