There is a lot of good advice here, but let me add my 2 cents 1. good wifi - a lot of hackathons are not prepared for the number of devices connected when 100

There is a lot of good advice here, but let me add my 2 cents 1. good wifi - a lot of hackathons are not prepared for the number of devices connected when 100 people arrive... 2. set a clear schedule. My favorite is Fri night - intro session, people present ideas, team building Sat morning - starting to work 10am workshops at 11am end of coding Sun at 12pm presentations Sun 1-3pm Judgement - 4pm 3. team building is a critical part in the event. I normally have a few people from the organizing team helping people find who to work with. We have tried using colored stickers for different expertise - developers, designers, ideas, FEDs, etc. Most hackathons do not have sufficient designers. 4. Food - keep in mind that Pizza is great for males. But women may like lighter food. Given you have an over-night event, you need to take care of that. Same goes for beer - have a wine option 5. As many organizers as possible in the event. People have questions and need help all the time. The more people you have to help the better.