The more, the merrier, if well fed with good wifi
Co-Founder of OverClock, Angel Hack & Hackathon.io, Coding & Hacking Expert
Key hackathon ingredients: wifi, food, space, private areas, key contacts, fun, games, & structure.
You can come to a hackathon with your own team or form a team there.
Founding teams often form at hackathons and go on to raise money and establish a company.
Be as minimal as possible.
If team is together, use pen and paper; if you need to communicate remotely, try Balsamiq.
Hacking gets straight down to the code vs. the preliminary planning of product development.