The Startup Weekend judging criteria is broken up into three sections. Teams are judged according to the following 3 criteria (weighted equally)
How does the team plan on making this a successful business? Have they thought about (either solved or identified problems) competition, how to scale, acquiring customers, their revenue model etc?
Are teams building something that people actually want? How well does the team understand their customer and their customer’s needs. Did the team get out and talk to customers? What is the value proposition to customers?
Execution & Design
Have they established a “Minimal Viable Product” for the weekend (software, hardware, etc.)? *Note: an MVP is the minimum set of features to be able to start collecting data. Does it deliver a compelling and captivating user experience? Were they able to demo something functional?