This document provides guidance for participants in a hackathon event called HackU. It defines hacking as constructively altering a system to do what you want using available resources. HackU is described as 24 hours of non-stop coding and innovation where participants are encouraged to build something they will personally use, show what can be built with available systems, and present their work at the end. Tips are provided such as focusing on one innovative idea, using available APIs, code libraries and development tools from Yahoo and others, and preparing a backup demo in case of technical issues.