What is Hackathon?
Hackathon meaning An event, usually over one or two days, where developers, subject experts and others come together to create apps, visualisations and prototypes that aim to address problems in a particular domain, usually making heavy use of data. Hackathons focusing on a particular collection of data are a possible form of community engagement by data publishers. The hackathon is a popular format in the open source community.
reference: Open Data Handbook – Glossary