I have organized Fukuoka Global Game Jam (GGJ) since 2011 and also have had charge of a GGJ regional organizer for Japan Region since 2013.
GGJ is the largest annual Hackathon holding a Guinness world record as over than 20,000 participators . Every last weekend of January, GGJ holds by over than 500 local Hackathon site. Game creators gather a near site and build their team on site. Then, they develop a game according to the theme which GGJ community decides before. Over than 5,000 games developed in the weekend all over the world.
In Fukuoka GGJ, every year, we connected other oversees sites to communicate between participators. These two pictures are an appearance of Fukuoka GGJ.