This document summarizes lessons learned from the Global Game Jam 2010 event. The main lessons are: (1) plan for the worst case scenario and bet on it, (2) doing is faster than arguing so throw out prototypes and fail fast, and (3) play with what you have now to fill the gap between ambition and ability by balancing time, scope, and resources. Other lessons include going alone to go fast but together to go far, getting into the rhythm of game development by eating your own dog food, and that game jams provide a full experience to develop skills as a game developer. The conclusion encourages participants to make games at future Global Game Jam events held annually in January.