GRASS GIS (Geographic Resources Analysis Support System) is an open source, Free Software Geographical Information System (GIS) with raster, topological vector, image processing, and graphics production functionality that operates on various platforms through a graphical user interface and shell in X-Window. It is released under GNU General Public License (GPL)
Esri devMeetUps - locate a developer meetup taking place in a city near you
ERDAS Webinars - Register for a free, online webinar from ERDAS
ILMF 2012 - International LiDAR Mapping Forum, Denver, Colorado, Jan 23-25, 2012
Esri Dev Summit - The Esri Developer Summit (DevSummit) brings together developers and GIS professionals from all over the globe. March 26-29, 2012, Palm Springs, CA
Where2.0 - where the people working on and using location technologies come together to explore best practices and emerging trends in software development, tools, business strategies, and marketing. April 2-4, 20112, San Francisco, CA