O'Reilly OSCON - Huge open source convention on the West coast.
Ohio Linux Fest - The Ohio LinuxFest is a free, grassroots conference for the Linux/Open Source Software/Free Software community that started in 2003 as a large inter-LUG meeting and has grown steadily since. It is a place for the community to gather and share information about Linux and Open Source Software.
Geeknic - A geeknic is rather simply a picnic for geeks. Throughout 2009, we’re planning (and helping others plan) geeknics all over the world. Anywhere there are geeks, we would love to see a geeknic happen.
Open Source Bridge - Open Source Bridge is a new conference for developers working with open source technologies and for people interested in learning the open source way. It’s not a typical technical conference.