HACKmemphis is an organization that hosts a weekend hackathon event. They encourage developers and designers of any background (or technology) to come together to work on whatever projects interest them.
HACKmemphis is a free form weekend of hacking on software and hardware projects. Last year there were over 50 participants over the course of the 2 day event.
This year they're starting earlier, on Friday September 19th and will continue throughout Saturday and into Sunday morning where there will do a brief demo of the projects worked on over the weekend.